From e8eccde8db246d262d7a9e1c6088cc24e82c84e8 Mon Sep 17 00:00:00 2001
From: Matthias Melcher <github@matthiasm.com>
Date: Wed, 19 Jul 2023 20:41:58 +0200
Subject: [PATCH] FLUID: RTTI improvements, 'is_a90' now const, apply RTTI

---
 examples/fluid-callback.fl |   5 ++
 fluid/Fd_Snap_Action.cxx   |   2 +-
 fluid/Fl_Button_Type.cxx   |  10 +--
 fluid/Fl_Button_Type.h     |   2 +-
 fluid/Fl_Function_Type.cxx |   6 +-
 fluid/Fl_Function_Type.h   |  17 ++--
 fluid/Fl_Group_Type.cxx    |  30 ++++---
 fluid/Fl_Group_Type.h      |  19 ++--
 fluid/Fl_Menu_Type.cxx     |  34 +++----
 fluid/Fl_Menu_Type.h       |  22 ++---
 fluid/Fl_Type.cxx          |   6 +-
 fluid/Fl_Type.h            |  14 ++-
 fluid/Fl_Widget_Type.cxx   | 176 +++++++++++++++++--------------------
 fluid/Fl_Widget_Type.h     |   3 +-
 fluid/Fl_Window_Type.cxx   |  72 ++++++++-------
 fluid/Fl_Window_Type.h     |   5 +-
 fluid/code.cxx             |  10 +--
 fluid/custom_widgets.cxx   |   2 +-
 fluid/factory.cxx          |  58 ++++++------
 fluid/fluid.cxx            |   4 +-
 fluid/widget_browser.cxx   |   6 +-
 test/checkers_pieces.fl    |   5 ++
 test/mandelbrot_ui.fl      |   5 ++
 test/tabs.fl               |   5 ++
 24 files changed, 261 insertions(+), 257 deletions(-)

diff --git a/examples/fluid-callback.fl b/examples/fluid-callback.fl
index ac993fbc7..3222f7382 100644
--- a/examples/fluid-callback.fl
+++ b/examples/fluid-callback.fl
@@ -2,6 +2,11 @@
 version 1.0400
 header_name {.h}
 code_name {.cxx}
+snap {
+  ver 1
+  current_suite FLTK
+  current_preset 0
+}
 comment {README FIRST
 - - - - - - -
 This fluid (.fl) file demonstrates how to create a complete
diff --git a/fluid/Fd_Snap_Action.cxx b/fluid/Fd_Snap_Action.cxx
index 6f7531007..cc1debf2f 100644
--- a/fluid/Fd_Snap_Action.cxx
+++ b/fluid/Fd_Snap_Action.cxx
@@ -922,7 +922,7 @@ static bool in_group(Fd_Snap_Data &d) {
 }
 
 static bool in_tabs(Fd_Snap_Data &d) {
-  return (d.wgt && d.wgt->parent && d.wgt->parent->is_tabs());
+  return (d.wgt && d.wgt->parent && d.wgt->parent->is_a(Fl_Type::ID_Tabs));
 }
 
 static Fl_Group *parent(Fd_Snap_Data &d) {
diff --git a/fluid/Fl_Button_Type.cxx b/fluid/Fl_Button_Type.cxx
index 7de4895a1..53355b7c3 100644
--- a/fluid/Fl_Button_Type.cxx
+++ b/fluid/Fl_Button_Type.cxx
@@ -85,7 +85,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Return_Button_Type(); }
   ID id() const FL_OVERRIDE { return ID_Return_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Return_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Return_Button) ? true : super::is_a(inID); }
 };
 
 Fl_Return_Button_Type Fl_Return_Button_type;
@@ -110,7 +110,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Repeat_Button_Type(); }
   ID id() const FL_OVERRIDE { return ID_Repeat_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Repeat_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Repeat_Button) ? true : super::is_a(inID); }
 };
 
 Fl_Repeat_Button_Type Fl_Repeat_Button_type;
@@ -137,7 +137,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Light_Button_Type(); }
   ID id() const FL_OVERRIDE { return ID_Light_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Light_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Light_Button) ? true : super::is_a(inID); }
 };
 
 Fl_Light_Button_Type Fl_Light_Button_type;
@@ -164,7 +164,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Check_Button_Type(); }
   ID id() const FL_OVERRIDE { return ID_Check_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Check_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Check_Button) ? true : super::is_a(inID); }
 };
 
 Fl_Check_Button_Type Fl_Check_Button_type;
@@ -191,7 +191,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Round_Button_Type(); }
   ID id() const FL_OVERRIDE { return ID_Round_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Round_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Round_Button) ? true : super::is_a(inID); }
 };
 
 Fl_Round_Button_Type Fl_Round_Button_type;
diff --git a/fluid/Fl_Button_Type.h b/fluid/Fl_Button_Type.h
index 2013e1646..ea7ed7cd3 100644
--- a/fluid/Fl_Button_Type.h
+++ b/fluid/Fl_Button_Type.h
@@ -34,7 +34,7 @@ public:
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Button_Type(); }
   int is_button() const FL_OVERRIDE { return 1; }
   ID id() const FL_OVERRIDE { return ID_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Button) ? true : super::is_a(inID); }
 };
 
 extern Fl_Button_Type Fl_Button_type;
diff --git a/fluid/Fl_Function_Type.cxx b/fluid/Fl_Function_Type.cxx
index 0dfcea456..5b646790a 100644
--- a/fluid/Fl_Function_Type.cxx
+++ b/fluid/Fl_Function_Type.cxx
@@ -45,7 +45,7 @@ Fl_Class_Type *current_class = NULL;
 int has_toplevel_function(const char *rtype, const char *sig) {
   Fl_Type *child;
   for (child = Fl_Type::first; child; child = child->next) {
-    if (!child->is_in_class() && (child->id() == Fl_Type::ID_Function)) {
+    if (!child->is_in_class() && child->is_a(Fl_Type::ID_Function)) {
       const Fl_Function_Type *fn = (const Fl_Function_Type*)child;
       if (fn->has_signature(rtype, sig))
         return 1;
@@ -525,7 +525,7 @@ void Fl_Function_Type::write_code2(Fd_Code_Writer& f) {
   char havechildren = 0;
   for (child = next; child && child->level > level; child = child->next) {
     havechildren = 1;
-    if (child->is_window() && child->name()) var = child->name();
+    if (child->is_a(ID_Window) && child->name()) var = child->name();
   }
 
   if (ismain()) {
@@ -1982,7 +1982,7 @@ void Fl_Class_Type::write_code2(Fd_Code_Writer& f) {
 int Fl_Class_Type::has_function(const char *rtype, const char *sig) const {
   Fl_Type *child;
   for (child = next; child && child->level > level; child = child->next) {
-    if (child->level == level+1 && (child->id() == Fl_Type::ID_Function)) {
+    if (child->level == level+1 && child->is_a(Fl_Type::ID_Function)) {
       const Fl_Function_Type *fn = (const Fl_Function_Type*)child;
       if (fn->has_signature(rtype, sig))
         return 1;
diff --git a/fluid/Fl_Function_Type.h b/fluid/Fl_Function_Type.h
index d844016c9..1af161374 100644
--- a/fluid/Fl_Function_Type.h
+++ b/fluid/Fl_Function_Type.h
@@ -64,7 +64,7 @@ public:
   int is_code_block() const FL_OVERRIDE {return 1;}
   int is_public() const FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Function; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Function) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Function) ? true : super::is_a(inID); }
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
   int has_signature(const char *, const char*) const;
@@ -91,7 +91,7 @@ public:
   int is_code_block() const FL_OVERRIDE {return 0;}
   int is_code() const FL_OVERRIDE {return 1;}
   ID id() const FL_OVERRIDE { return ID_Code; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Code) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Code) ? true : super::is_a(inID); }
   int is_public() const FL_OVERRIDE { return -1; }
   int is_editing();
   int reap_editor();
@@ -117,7 +117,7 @@ public:
   int is_parent() const FL_OVERRIDE {return 1;}
   int is_public() const FL_OVERRIDE { return -1; }
   ID id() const FL_OVERRIDE { return ID_CodeBlock; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_CodeBlock) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_CodeBlock) ? true : super::is_a(inID); }
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
 };
@@ -143,7 +143,7 @@ public:
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
   int is_public() const FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Decl; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Decl) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Decl) ? true : super::is_a(inID); }
 };
 
 // ---- Fl_Data_Type declaration
@@ -165,7 +165,7 @@ public:
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Data; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Data) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Data) ? true : super::is_a(inID); }
 };
 
 // ---- Fl_DeclBlock_Type declaration
@@ -190,7 +190,7 @@ public:
   int is_decl_block() const FL_OVERRIDE {return 1;}
   int is_public() const FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_DeclBlock; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_DeclBlock) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_DeclBlock) ? true : super::is_a(inID); }
 };
 
 // ---- Fl_Comment_Type declaration
@@ -212,9 +212,8 @@ public:
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
   int is_public() const FL_OVERRIDE { return 1; }
-  int is_comment() const FL_OVERRIDE { return 1; }
   ID id() const FL_OVERRIDE { return ID_Comment; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Comment) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Comment) ? true : super::is_a(inID); }
 };
 
 // ---- Fl_Class_Type declaration
@@ -243,7 +242,7 @@ public:
   int is_class() const FL_OVERRIDE {return 1;}
   int is_public() const FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Class; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Class) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Class) ? true : super::is_a(inID); }
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
 
diff --git a/fluid/Fl_Group_Type.cxx b/fluid/Fl_Group_Type.cxx
index 605dd0797..06d5e8013 100644
--- a/fluid/Fl_Group_Type.cxx
+++ b/fluid/Fl_Group_Type.cxx
@@ -57,6 +57,9 @@ Fl_Type *Fl_Group_Type::make(Strategy strategy) {
   return Fl_Widget_Type::make(strategy);
 }
 
+/**
+ \brief Enlarge the group size, so all children fit within.
+ */
 void fix_group_size(Fl_Type *tt) {
   if (!tt || !tt->is_group()) return;
   Fl_Group_Type* t = (Fl_Group_Type*)tt;
@@ -65,12 +68,13 @@ void fix_group_size(Fl_Type *tt) {
   int R = X+t->o->w();
   int B = Y+t->o->h();
   for (Fl_Type *nn = t->next; nn && nn->level > t->level; nn = nn->next) {
-    if (!nn->is_widget() || nn->is_menu_item()) continue;
-    Fl_Widget_Type* n = (Fl_Widget_Type*)nn;
-    int x = n->o->x();  if (x < X) X = x;
-    int y = n->o->y();  if (y < Y) Y = y;
-    int r = x+n->o->w();if (r > R) R = r;
-    int b = y+n->o->h();if (b > B) B = b;
+    if (nn->is_true_widget()) {
+      Fl_Widget_Type* n = (Fl_Widget_Type*)nn;
+      int x = n->o->x();  if (x < X) X = x;
+      int y = n->o->y();  if (y < Y) Y = y;
+      int r = x+n->o->w();if (r > R) R = r;
+      int b = y+n->o->h();if (b > B) B = b;
+    }
   }
   t->o->resize(X,Y,R-X,B-Y);
 }
@@ -78,8 +82,8 @@ void fix_group_size(Fl_Type *tt) {
 void group_cb(Fl_Widget *, void *) {
   // Find the current widget:
   Fl_Type *qq = Fl_Type::current;
-  while (qq && (!qq->is_widget() || qq->is_menu_item())) qq = qq->parent;
-  if (!qq || qq->level < 1 || (qq->level == 1 && (qq->id() == Fl_Type::ID_Widget_Class))) {
+  while (qq && !qq->is_true_widget()) qq = qq->parent;
+  if (!qq || qq->level < 1 || (qq->level == 1 && qq->is_a(Fl_Type::ID_Widget_Class))) {
     fl_message("Please select widgets to group");
     return;
   }
@@ -106,9 +110,9 @@ void group_cb(Fl_Widget *, void *) {
 void ungroup_cb(Fl_Widget *, void *) {
   // Find the group:
   Fl_Type *q = Fl_Type::current;
-  while (q && (!q->is_widget() || q->is_menu_item())) q = q->parent;
+  while (q && !q->is_true_widget()) q = q->parent;
   if (q) q = q->parent;
-  if (!q || q->level < 1 || (q->level == 1 && (q->id() == Fl_Type::ID_Widget_Class))) {
+  if (!q || q->level < 1 || (q->level == 1 && q->is_a(Fl_Type::ID_Widget_Class))) {
     fl_message("Please select widgets in a group");
     return;
   }
@@ -399,13 +403,13 @@ void Fl_Flex_Type::change_subtype_to(int n) {
 int Fl_Flex_Type::parent_is_flex(Fl_Type *t) {
   return (t->is_widget()
           && t->parent
-          && t->parent->is_flex());
+          && t->parent->is_a(ID_Flex));
 }
 
 int Fl_Flex_Type::size(Fl_Type *t, char fixed_only) {
   if (!t->is_widget()) return 0;
   if (!t->parent) return 0;
-  if (!t->parent->is_flex()) return 0;
+  if (!t->parent->is_a(ID_Flex)) return 0;
   Fl_Flex_Type* ft = (Fl_Flex_Type*)t->parent;
   Fl_Flex* f = (Fl_Flex*)ft->o;
   Fl_Widget *w = ((Fl_Widget_Type*)t)->o;
@@ -416,7 +420,7 @@ int Fl_Flex_Type::size(Fl_Type *t, char fixed_only) {
 int Fl_Flex_Type::is_fixed(Fl_Type *t) {
   if (!t->is_widget()) return 0;
   if (!t->parent) return 0;
-  if (!t->parent->is_flex()) return 0;
+  if (!t->parent->is_a(ID_Flex)) return 0;
   Fl_Flex_Type* ft = (Fl_Flex_Type*)t->parent;
   Fl_Flex* f = (Fl_Flex*)ft->o;
   Fl_Widget *w = ((Fl_Widget_Type*)t)->o;
diff --git a/fluid/Fl_Group_Type.h b/fluid/Fl_Group_Type.h
index d98e6121c..9b6b83404 100644
--- a/fluid/Fl_Group_Type.h
+++ b/fluid/Fl_Group_Type.h
@@ -54,7 +54,7 @@ public:
   int is_parent() const FL_OVERRIDE {return 1;}
   int is_group() const FL_OVERRIDE {return 1;}
   ID id() const FL_OVERRIDE { return ID_Group; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Group) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Group) ? true : super::is_a(inID); }
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
   void leave_live_mode() FL_OVERRIDE;
   void copy_properties() FL_OVERRIDE;
@@ -74,7 +74,7 @@ public:
   const char *alt_type_name() FL_OVERRIDE {return "fltk::PackedGroup";}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Pack_Type();}
   ID id() const FL_OVERRIDE { return ID_Pack; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Pack) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Pack) ? true : super::is_a(inID); }
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
   void copy_properties() FL_OVERRIDE;
 };
@@ -99,7 +99,7 @@ public:
   Fl_Widget *widget(int X,int Y,int W,int H) FL_OVERRIDE {
     Fl_Flex *g = new Fl_Flex(X,Y,W,H); Fl_Group::current(0); return g;}
   ID id() const FL_OVERRIDE { return ID_Flex; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Flex) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Flex) ? true : super::is_a(inID); }
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
   void read_property(Fd_Project_Reader &f, const char *) FL_OVERRIDE;
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
@@ -109,7 +109,6 @@ public:
   void add_child(Fl_Type*, Fl_Type*) FL_OVERRIDE;
   void move_child(Fl_Type*, Fl_Type*) FL_OVERRIDE;
   void remove_child(Fl_Type*) FL_OVERRIDE;
-  int is_flex() const FL_OVERRIDE {return 1;}
   void change_subtype_to(int n);
   static int parent_is_flex(Fl_Type*);
   static int size(Fl_Type*, char fixed_only=0);
@@ -128,7 +127,7 @@ public:
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Table_Type(); }
   Fl_Widget *widget(int X, int Y, int W, int H) FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Table; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Table) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Table) ? true : super::is_a(inID); }
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
   void add_child(Fl_Type*, Fl_Type*) FL_OVERRIDE;
   void move_child(Fl_Type*, Fl_Type*) FL_OVERRIDE;
@@ -159,9 +158,8 @@ public:
   void add_child(Fl_Type*, Fl_Type*) FL_OVERRIDE;
   void remove_child(Fl_Type*) FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Tabs; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Tabs) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Tabs) ? true : super::is_a(inID); }
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
-  int is_tabs() const FL_OVERRIDE {return 1;}
 };
 
 // ---- Fl_Scroll_Type ------------------------------------------------- MARK: -
@@ -178,10 +176,9 @@ public:
   const char *alt_type_name() FL_OVERRIDE {return "fltk::ScrollGroup";}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Scroll_Type();}
   ID id() const FL_OVERRIDE { return ID_Scroll; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Scroll) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Scroll) ? true : super::is_a(inID); }
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
   void copy_properties() FL_OVERRIDE;
-  int is_scroll() const FL_OVERRIDE { return 1; }
 };
 
 // ---- Fl_Tile_Type --------------------------------------------------- MARK: -
@@ -196,7 +193,7 @@ public:
   const char *alt_type_name() FL_OVERRIDE {return "fltk::TileGroup";}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Tile_Type();}
   ID id() const FL_OVERRIDE { return ID_Tile; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Tile) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Tile) ? true : super::is_a(inID); }
   void copy_properties() FL_OVERRIDE;
 };
 
@@ -221,7 +218,7 @@ public:
     iwizard *g = new iwizard(X,Y,W,H); Fl_Group::current(0); return g;}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Wizard_Type();}
   ID id() const FL_OVERRIDE { return ID_Wizard; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Wizard) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Wizard) ? true : super::is_a(inID); }
 };
 
 #endif // _FLUID_FL_GROUP_TYPE_H
diff --git a/fluid/Fl_Menu_Type.cxx b/fluid/Fl_Menu_Type.cxx
index 7b582e65b..28f77175f 100644
--- a/fluid/Fl_Menu_Type.cxx
+++ b/fluid/Fl_Menu_Type.cxx
@@ -137,7 +137,7 @@ void Fl_Input_Choice_Type::build_menu() {
       if (q->is_parent()) {lvl++; m->flags |= FL_SUBMENU;}
       m++;
       int l1 =
-        (q->next && q->next->is_menu_item()) ? q->next->level : level;
+        (q->next && q->next->is_a(ID_Menu_Item)) ? q->next->level : level;
       while (lvl > l1) {m->label(0); m++; lvl--;}
       lvl = l1;
     }
@@ -155,10 +155,10 @@ Fl_Type *Fl_Menu_Item_Type::make(Strategy strategy) {
   Fl_Type* q = Fl_Type::current;
   Fl_Type* p = q;
   if (p) {
-    if ( (force_parent && q->is_menu_item()) || !q->is_parent()) p = p->parent;
+    if ( (force_parent && q->is_a(ID_Menu_Item)) || !q->is_parent()) p = p->parent;
   }
   force_parent = 0;
-  if (!p || !(p->is_a(ID_Menu_Manager_) || (p->is_menu_item() && p->is_parent()))) {
+  if (!p || !(p->is_a(ID_Menu_Manager_) || p->is_a(ID_Submenu))) {
     fl_message("Please select a menu to add to");
     return 0;
   }
@@ -230,7 +230,7 @@ int isdeclare(const char *c);
 const char* Fl_Menu_Item_Type::menu_name(Fd_Code_Writer& f, int& i) {
   i = 0;
   Fl_Type* t = prev;
-  while (t && t->is_menu_item()) {
+  while (t && t->is_a(ID_Menu_Item)) {
     // be sure to count the {0} that ends a submenu:
     if (t->level > t->next->level) i += (t->level - t->next->level);
     // detect empty submenu:
@@ -290,14 +290,14 @@ void Fl_Menu_Item_Type::write_static(Fd_Code_Writer& f) {
     if (k) {
       f.write_c("void %s::%s(Fl_Menu_* o, %s v) {\n", k, cn, ut);
       f.write_c("%s((%s*)(o", f.indent(1), k);
-      Fl_Type* t = parent; while (t->is_menu_item()) t = t->parent;
+      Fl_Type* t = parent; while (t->is_a(ID_Menu_Item)) t = t->parent;
       Fl_Type *q = 0;
       // Go up one more level for Fl_Input_Choice, as these are groups themselves
-      if (t && (t->id() == Fl_Type::ID_Input_Choice))
+      if (t && t->is_a(Fl_Type::ID_Input_Choice))
         f.write_c("->parent()");
       for (t = t->parent; t && t->is_widget() && !is_class(); q = t, t = t->parent)
         f.write_c("->parent()");
-      if (!q || (q->id() != Fl_Type::ID_Widget_Class))
+      if (!q || !q->is_a(Fl_Type::ID_Widget_Class))
         f.write_c("->user_data()");
       f.write_c("))->%s_i(o,v);\n}\n", cn);
     }
@@ -306,7 +306,7 @@ void Fl_Menu_Item_Type::write_static(Fd_Code_Writer& f) {
     if (!f.c_contains(image))
       image->write_static(f, compress_image_);
   }
-  if (next && next->is_menu_item()) return;
+  if (next && next->is_a(ID_Menu_Item)) return;
   // okay, when we hit last item in the menu we have to write the
   // entire array out:
   const char* k = class_name(1);
@@ -317,20 +317,20 @@ void Fl_Menu_Item_Type::write_static(Fd_Code_Writer& f) {
     int i;
     f.write_c("\nFl_Menu_Item %s[] = {\n", menu_name(f, i));
   }
-  Fl_Type* t = prev; while (t && t->is_menu_item()) t = t->prev;
-  for (Fl_Type* q = t->next; q && q->is_menu_item(); q = q->next) {
+  Fl_Type* t = prev; while (t && t->is_a(ID_Menu_Item)) t = t->prev;
+  for (Fl_Type* q = t->next; q && q->is_a(ID_Menu_Item); q = q->next) {
     ((Fl_Menu_Item_Type*)q)->write_item(f);
     int thislevel = q->level; if (q->is_parent()) thislevel++;
     int nextlevel =
-      (q->next && q->next->is_menu_item()) ? q->next->level : t->level+1;
+      (q->next && q->next->is_a(ID_Menu_Item)) ? q->next->level : t->level+1;
     while (thislevel > nextlevel) {f.write_c(" {0,0,0,0,0,0,0,0,0},\n"); thislevel--;}
   }
   f.write_c(" {0,0,0,0,0,0,0,0,0}\n};\n");
 
   if (k) {
     // Write menu item variables...
-    t = prev; while (t && t->is_menu_item()) t = t->prev;
-    for (Fl_Type* q = t->next; q && q->is_menu_item(); q = q->next) {
+    t = prev; while (t && t->is_a(ID_Menu_Item)) t = t->prev;
+    for (Fl_Type* q = t->next; q && q->is_a(ID_Menu_Item); q = q->next) {
       Fl_Menu_Item_Type *m = (Fl_Menu_Item_Type*)q;
       const char *c = array_name(m);
       if (c) {
@@ -433,7 +433,7 @@ void start_menu_initialiser(Fd_Code_Writer& f, int &initialized, const char *nam
 void Fl_Menu_Item_Type::write_code1(Fd_Code_Writer& f) {
   int i; const char* mname = menu_name(f, i);
 
-  if (!prev->is_menu_item()) {
+  if (!prev->is_a(ID_Menu_Item)) {
     // for first menu item, declare the array
     if (class_name(1)) {
       f.write_h("%sstatic Fl_Menu_Item %s[];\n", f.indent(1), mname);
@@ -588,7 +588,7 @@ void Fl_Menu_Base_Type::build_menu() {
       if (q->is_parent()) {lvl++; m->flags |= FL_SUBMENU;}
       m++;
       int l1 =
-        (q->next && q->next->is_menu_item()) ? q->next->level : level;
+        (q->next && q->next->is_a(ID_Menu_Item)) ? q->next->level : level;
       while (lvl > l1) {m->label(0); m++; lvl--;}
       lvl = l1;
     }
@@ -616,7 +616,7 @@ Fl_Type* Fl_Menu_Base_Type::click_test(int, int) {
 }
 
 void Fl_Menu_Manager_Type::write_code2(Fd_Code_Writer& f) {
-  if (next && next->is_menu_item()) {
+  if (next && next->is_a(ID_Menu_Item)) {
     f.write_c("%s%s->menu(%s);\n", f.indent(), name() ? name() : "o",
             f.unique_id(this, "menu", name(), label()));
   }
@@ -718,7 +718,7 @@ void shortcut_in_cb(Fl_Shortcut_Button* i, void* v) {
         Fl_Button* b = (Fl_Button*)(((Fl_Widget_Type*)o)->o);
         if (b->shortcut() != (int)i->value()) mod = 1;
         b->shortcut(i->value());
-        if (o->is_menu_item()) ((Fl_Widget_Type*)o)->redraw();
+        if (o->is_a(Fl_Type::ID_Menu_Item)) ((Fl_Widget_Type*)o)->redraw();
       } else if (o->selected && o->is_a(Fl_Type::ID_Input)) {
         Fl_Input_* b = (Fl_Input_*)(((Fl_Widget_Type*)o)->o);
         if (b->shortcut() != (int)i->value()) mod = 1;
diff --git a/fluid/Fl_Menu_Type.h b/fluid/Fl_Menu_Type.h
index f6238930b..a18e4edef 100644
--- a/fluid/Fl_Menu_Type.h
+++ b/fluid/Fl_Menu_Type.h
@@ -48,7 +48,6 @@ public:
   const char* type_name() FL_OVERRIDE {return "MenuItem";}
   const char* alt_type_name() FL_OVERRIDE {return "fltk::Item";}
   Fl_Type* make(Strategy strategy) FL_OVERRIDE;
-  int is_menu_item() const FL_OVERRIDE {return 1;}
   int is_button() const FL_OVERRIDE {return 1;} // this gets shortcut to work
   Fl_Widget* widget(int,int,int,int) FL_OVERRIDE {return 0;}
   Fl_Widget_Type* _make() FL_OVERRIDE {return 0;}
@@ -58,8 +57,9 @@ public:
   void write_item(Fd_Code_Writer& f);
   void write_code1(Fd_Code_Writer& f) FL_OVERRIDE;
   void write_code2(Fd_Code_Writer& f) FL_OVERRIDE;
+  int is_true_widget() const FL_OVERRIDE { return 0; }
   ID id() const FL_OVERRIDE { return ID_Menu_Item; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Menu_Item) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Menu_Item) ? true : super::is_a(inID); }
 };
 
 /**
@@ -72,7 +72,7 @@ public:
   const char* type_name() FL_OVERRIDE {return "RadioMenuItem";}
   Fl_Type* make(Strategy strategy) FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Radio_Menu_Item; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Radio_Menu_Item) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Radio_Menu_Item) ? true : super::is_a(inID); }
 };
 
 /**
@@ -85,7 +85,7 @@ public:
   const char* type_name() FL_OVERRIDE {return "CheckMenuItem";}
   Fl_Type* make(Strategy strategy) FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Checkbox_Menu_Item; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Checkbox_Menu_Item) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Checkbox_Menu_Item) ? true : super::is_a(inID); }
 };
 
 /**
@@ -111,7 +111,7 @@ public:
   void move_child(Fl_Type*a, Fl_Type*b) FL_OVERRIDE {parent->move_child(a,b);}
   void remove_child(Fl_Type*a) FL_OVERRIDE {parent->remove_child(a);}
   ID id() const FL_OVERRIDE { return ID_Submenu; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Submenu) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Submenu) ? true : super::is_a(inID); }
 };
 
 // -----------------------------------------------------------------------------
@@ -136,7 +136,7 @@ public:
   void write_code2(Fd_Code_Writer& f) FL_OVERRIDE;
   void copy_properties() FL_OVERRIDE = 0;
   ID id() const FL_OVERRIDE { return ID_Menu_Manager_; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Menu_Manager_) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Menu_Manager_) ? true : super::is_a(inID); }
 };
 
 /**
@@ -185,7 +185,7 @@ public:
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Input_Choice_Type();}
   void build_menu() FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Input_Choice; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Input_Choice) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Input_Choice) ? true : super::is_a(inID); }
   void copy_properties() FL_OVERRIDE;
 };
 
@@ -215,7 +215,7 @@ public:
   Fl_Type* click_test(int x, int y) FL_OVERRIDE;
   void copy_properties() FL_OVERRIDE;
   ID id() const FL_OVERRIDE { return ID_Menu_; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Menu_) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Menu_) ? true : super::is_a(inID); }
 };
 
 extern Fl_Menu_Item button_type_menu[];
@@ -241,7 +241,7 @@ public:
     return new Fl_Menu_Button(X,Y,W,H,"menu");}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Menu_Button_Type();}
   ID id() const FL_OVERRIDE { return ID_Menu_Button; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Menu_Button) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Menu_Button) ? true : super::is_a(inID); }
 };
 
 
@@ -272,7 +272,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Choice_Type();}
   ID id() const FL_OVERRIDE { return ID_Choice; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Choice) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Choice) ? true : super::is_a(inID); }
 };
 
 
@@ -293,7 +293,7 @@ public:
   Fl_Widget *widget(int X,int Y,int W,int H) FL_OVERRIDE {return new Fl_Menu_Bar(X,Y,W,H);}
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Menu_Bar_Type();}
   ID id() const FL_OVERRIDE { return ID_Menu_Bar; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Menu_Bar) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Menu_Bar) ? true : super::is_a(inID); }
 };
 
 
diff --git a/fluid/Fl_Type.cxx b/fluid/Fl_Type.cxx
index 110122a1e..9ed867151 100644
--- a/fluid/Fl_Type.cxx
+++ b/fluid/Fl_Type.cxx
@@ -409,7 +409,7 @@ Fl_Window_Type *Fl_Type::window() {
   if (!is_widget())
     return NULL;
   for (Fl_Type *t = this; t; t=t->parent)
-    if (t->is_window())
+    if (t->is_a(ID_Window))
       return (Fl_Window_Type*)t;
   return NULL;
 }
@@ -584,7 +584,7 @@ Fl_Type *Fl_Type::remove() {
 }
 
 void Fl_Type::name(const char *n) {
-  int nostrip = is_comment();
+  int nostrip = is_a(Fl_Type::ID_Comment);
   if (storestring(n,name_,nostrip)) {
     if (visible) widget_browser->redraw();
   }
@@ -842,7 +842,7 @@ void Fl_Type::copy_properties() {
  */
 int Fl_Type::user_defined(const char* cbname) const {
   for (Fl_Type* p = Fl_Type::first; p ; p = p->next)
-    if ((p->id() == Fl_Type::ID_Function) && p->name() != 0)
+    if (p->is_a(Fl_Type::ID_Function) && p->name() != 0)
       if (strncmp(p->name(), cbname, strlen(cbname)) == 0)
         if (p->name()[strlen(cbname)] == '(')
           return 1;
diff --git a/fluid/Fl_Type.h b/fluid/Fl_Type.h
index 85879fea9..ad8edff01 100644
--- a/fluid/Fl_Type.h
+++ b/fluid/Fl_Type.h
@@ -182,25 +182,23 @@ public:
   int msgnum();
 
   // fake rtti:
+  /** Return 1 if the Type chn have children. */
   virtual int is_parent() const {return 0;}
+  /** Return 1 if the type is a widget or menu item. */
   virtual int is_widget() const {return 0;}
-  /// TODO: Misnamed: This is true if the widget is a button or a menu item with button functionality
+  /** Return 1 if the type is a widget but not a menu item. */
+  virtual int is_true_widget() const {return 0;}
+  /** Return 1 if a type behaves like a button (Fl_Button and Fl_Menu_Item and derived. */
   virtual int is_button() const {return 0;}
-  virtual int is_menu_item() const {return 0;}
   virtual int is_group() const {return 0;}
-  virtual int is_tabs() const {return 0;}
-  virtual int is_scroll() const {return 0;}
-  virtual int is_flex() const {return 0;}
-  virtual int is_window() const {return 0;}
   virtual int is_code() const {return 0;}
   virtual int is_code_block() const {return 0;}
   virtual int is_decl_block() const {return 0;}
-  virtual int is_comment() const {return 0;}
   virtual int is_class() const {return 0;}
   virtual int is_public() const {return 1;}
 
   virtual ID id() const { return ID_Base_; }
-  virtual bool is_a(ID inID) { return (inID==ID_Base_); }
+  virtual bool is_a(ID inID) const { return (inID==ID_Base_); }
 
   const char* class_name(const int need_nest) const;
   const class Fl_Class_Type* is_in_class() const;
diff --git a/fluid/Fl_Widget_Type.cxx b/fluid/Fl_Widget_Type.cxx
index 96631a149..f24b1d081 100644
--- a/fluid/Fl_Widget_Type.cxx
+++ b/fluid/Fl_Widget_Type.cxx
@@ -88,7 +88,7 @@ Fl_Widget_Type::ideal_size(int &w, int &h) {
 Fl_Type *Fl_Widget_Type::make(Strategy strategy) {
   // Find the current widget, or widget to copy:
   Fl_Type *qq = Fl_Type::current;
-  while (qq && (!qq->is_widget() || qq->is_menu_item())) qq = qq->parent;
+  while (qq && !qq->is_true_widget()) qq = qq->parent;
   if (!qq) {
     fl_message("Please select a widget");
     return 0;
@@ -104,7 +104,7 @@ Fl_Type *Fl_Widget_Type::make(Strategy strategy) {
   int B = p->o->w()/2; if (p->o->h()/2 < B) B = p->o->h()/2; if (B>25) B = 25;
 
   int ULX,ULY; // parent's origin in window
-  if (!p->is_window()) { // if it is a group, add corner
+  if (!p->is_a(ID_Window)) { // if it is a group, add corner
     ULX = p->o->x(); ULY = p->o->y();
   } else {
     ULX = ULY = 0;
@@ -151,7 +151,7 @@ Fl_Type *Fl_Widget_Type::make(Strategy strategy) {
 }
 
 void Fl_Widget_Type::setimage(Fluid_Image *i) {
-  if (i == image || is_window()) return;
+  if (i == image || is_a(ID_Window)) return;
   if (image) image->decrement();
   if (i) i->increment();
   image = i;
@@ -161,7 +161,7 @@ void Fl_Widget_Type::setimage(Fluid_Image *i) {
 }
 
 void Fl_Widget_Type::setinactive(Fluid_Image *i) {
-  if (i == inactive || is_window()) return;
+  if (i == inactive || is_a(ID_Window)) return;
   if (inactive) inactive->decrement();
   if (i) i->increment();
   inactive = i;
@@ -243,9 +243,9 @@ void Fl_Widget_Type::inactive_name(const char *n) {
 
 void Fl_Widget_Type::redraw() {
   Fl_Type *t = this;
-  if (is_menu_item()) {
+  if (is_a(ID_Menu_Item)) {
     // find the menu button that parents this menu:
-    do t = t->parent; while (t && t->is_menu_item());
+    do t = t->parent; while (t && t->is_a(ID_Menu_Item));
     // kludge to cause build_menu to be called again:
     if (t)
       t->add_child(0, 0);
@@ -261,7 +261,7 @@ Fl_Type *sort(Fl_Type *parent) {
   for (f = parent ? parent->next : Fl_Type::first; ; f = n) {
     if (!f || (parent && f->level <= parent->level)) return f;
     n = sort(f);
-    if (!f->selected || (!f->is_widget() || f->is_menu_item())) continue;
+    if (!f->selected || !f->is_true_widget()) continue;
     Fl_Widget* fw = ((Fl_Widget_Type*)f)->o;
     Fl_Type *g; // we will insert before this
     for (g = parent ? parent->next : Fl_Type::first; g != f; g = g->next) {
@@ -420,7 +420,7 @@ static Fl_Input *image_input;
 void image_cb(Fl_Input* i, void *v) {
   if (v == LOAD) {
     image_input = i;
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       i->activate();
       i->value(((Fl_Widget_Type*)current_widget)->image_name());
     } else i->deactivate();
@@ -438,7 +438,7 @@ void image_cb(Fl_Input* i, void *v) {
 
 void image_browse_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window())
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window))
       b->activate();
     else
       b->deactivate();
@@ -459,7 +459,7 @@ void image_browse_cb(Fl_Button* b, void *v) {
 
 void bind_image_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       b->activate();
       b->value(current_widget->bind_image_);
     } else {
@@ -479,7 +479,7 @@ void bind_image_cb(Fl_Button* b, void *v) {
 
 void compress_image_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       b->activate();
       b->value(current_widget->compress_image_);
     } else {
@@ -502,7 +502,7 @@ static Fl_Input *inactive_input;
 void inactive_cb(Fl_Input* i, void *v) {
   if (v == LOAD) {
     inactive_input = i;
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       i->activate();
       i->value(((Fl_Widget_Type*)current_widget)->inactive_name());
     } else i->deactivate();
@@ -520,7 +520,7 @@ void inactive_cb(Fl_Input* i, void *v) {
 
 void inactive_browse_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window())
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window))
       b->activate();
     else
       b->deactivate();
@@ -541,7 +541,7 @@ void inactive_browse_cb(Fl_Button* b, void *v) {
 
 void bind_deimage_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       b->activate();
       b->value(current_widget->bind_deimage_);
     } else {
@@ -561,7 +561,7 @@ void bind_deimage_cb(Fl_Button* b, void *v) {
 
 void compress_deimage_cb(Fl_Button* b, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_widget() && !current_widget->is_window()) {
+    if (current_widget->is_widget() && !current_widget->is_a(Fl_Type::ID_Window)) {
       b->activate();
       b->value(current_widget->compress_deimage_);
     } else {
@@ -757,7 +757,7 @@ Fluid_Coord_Input_Vars widget_vars[] = {
 void x_cb(Fluid_Coord_Input *i, void *v) {
   if (v == LOAD) {
     x_input = i;
-    if (current_widget->is_widget()) {
+    if (current_widget->is_true_widget()) {
       i->value(((Fl_Widget_Type *)current_widget)->o->x());
       x_input->activate();
     } else x_input->deactivate();
@@ -767,7 +767,7 @@ void x_cb(Fluid_Coord_Input *i, void *v) {
     int mod = 0;
     int v = 0;
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_widget()) {
+      if (o->selected && o->is_true_widget()) {
         Fl_Widget *w = ((Fl_Widget_Type *)o)->o;
         i->variables(widget_vars, o);
         v = i->value();
@@ -788,7 +788,7 @@ void x_cb(Fluid_Coord_Input *i, void *v) {
 void y_cb(Fluid_Coord_Input *i, void *v) {
   if (v == LOAD) {
     y_input = i;
-    if (current_widget->is_widget()) {
+    if (current_widget->is_true_widget()) {
       i->value(((Fl_Widget_Type *)current_widget)->o->y());
       y_input->activate();
     } else y_input->deactivate();
@@ -798,7 +798,7 @@ void y_cb(Fluid_Coord_Input *i, void *v) {
     int mod = 0;
     int v = 0;
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_widget()) {
+      if (o->selected && o->is_true_widget()) {
         Fl_Widget *w = ((Fl_Widget_Type *)o)->o;
         i->variables(widget_vars, o);
         v = i->value();
@@ -818,7 +818,7 @@ void y_cb(Fluid_Coord_Input *i, void *v) {
 void w_cb(Fluid_Coord_Input *i, void *v) {
   if (v == LOAD) {
     w_input = i;
-    if (current_widget->is_widget()) {
+    if (current_widget->is_true_widget()) {
       i->value(((Fl_Widget_Type *)current_widget)->o->w());
       w_input->activate();
     } else w_input->deactivate();
@@ -828,7 +828,7 @@ void w_cb(Fluid_Coord_Input *i, void *v) {
     int mod = 0;
     int v = 0;
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_widget()) {
+      if (o->selected && o->is_true_widget()) {
         Fl_Widget *w = ((Fl_Widget_Type *)o)->o;
         i->variables(widget_vars, o);
         v = i->value();
@@ -848,7 +848,7 @@ void w_cb(Fluid_Coord_Input *i, void *v) {
 void h_cb(Fluid_Coord_Input *i, void *v) {
   if (v == LOAD) {
     h_input = i;
-    if (current_widget->is_widget()) {
+    if (current_widget->is_true_widget()) {
       i->value(((Fl_Widget_Type *)current_widget)->o->h());
       h_input->activate();
     } else h_input->deactivate();
@@ -858,7 +858,7 @@ void h_cb(Fluid_Coord_Input *i, void *v) {
     int mod = 0;
     int v = 0;
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_widget()) {
+      if (o->selected && o->is_true_widget()) {
         Fl_Widget *w = ((Fl_Widget_Type *)o)->o;
         i->variables(widget_vars, o);
         v = i->value();
@@ -877,7 +877,7 @@ void h_cb(Fluid_Coord_Input *i, void *v) {
 
 void wc_relative_cb(Fl_Choice *i, void *v) {
   if (v == LOAD) {
-    if (current_widget->id() == Fl_Type::ID_Widget_Class) {
+    if (current_widget->is_a(Fl_Type::ID_Widget_Class)) {
       i->show();
       i->value(((Fl_Widget_Class_Type *)current_widget)->wc_relative);
     } else {
@@ -887,7 +887,7 @@ void wc_relative_cb(Fl_Choice *i, void *v) {
     int mod = 0;
     undo_checkpoint();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && (current_widget->id() == Fl_Type::ID_Widget_Class)) {
+      if (o->selected && current_widget->is_a(Fl_Type::ID_Widget_Class)) {
         Fl_Widget_Class_Type *t = (Fl_Widget_Class_Type *)o;
         t->wc_relative = i->value();
         mod = 1;
@@ -1021,7 +1021,7 @@ int boxnumber(const char *i) {
 
 void box_cb(Fl_Choice* i, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     int n = current_widget->o->box(); if (!n) n = ZERO_ENTRY;
     for (int j = 0; j < int(sizeof(boxmenu)/sizeof(*boxmenu)); j++)
       if (boxmenu[j].argument() == n) {i->value(j); break;}
@@ -1048,7 +1048,7 @@ void down_box_cb(Fl_Choice* i, void *v) {
     int n;
     if (current_widget->is_a(Fl_Type::ID_Button))
       n = ((Fl_Button*)(current_widget->o))->down_box();
-    else if (current_widget->id() == Fl_Type::ID_Input_Choice)
+    else if (current_widget->is_a(Fl_Type::ID_Input_Choice))
       n = ((Fl_Input_Choice*)(current_widget->o))->down_box();
     else if (current_widget->is_a(Fl_Type::ID_Menu_Manager_))
       n = ((Fl_Menu_*)(current_widget->o))->down_box();
@@ -1071,7 +1071,7 @@ void down_box_cb(Fl_Choice* i, void *v) {
           Fl_Widget_Type* q = (Fl_Widget_Type*)o;
           ((Fl_Button*)(q->o))->down_box((Fl_Boxtype)n);
           if (((Fl_Button*)(q->o))->value()) q->redraw();
-        } else if (o->id() == Fl_Type::ID_Input_Choice) {
+        } else if (o->is_a(Fl_Type::ID_Input_Choice)) {
           Fl_Widget_Type* q = (Fl_Widget_Type*)o;
           ((Fl_Input_Choice*)(q->o))->down_box((Fl_Boxtype)n);
         } else if (o->is_a(Fl_Type::ID_Menu_Manager_)) {
@@ -1146,7 +1146,7 @@ void set_whenmenu(int n) {
 
 void when_cb(Fl_Menu_Button* i, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     int n = current_widget->o->when();
     set_whenmenu(n);
     w_when_box->copy_label(when_symbol_name(n));
@@ -1175,26 +1175,8 @@ void when_cb(Fl_Menu_Button* i, void *v) {
   }
 }
 
-void when_button_cb(Fl_Box* i, void *v) {
-//  if (v == LOAD) {
-//    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
-//    i->value(current_widget->o->when()&FL_WHEN_NOT_CHANGED);
-//  } else {
-//    int mod = 0;
-//    int n = i->value() ? FL_WHEN_NOT_CHANGED : 0;
-//    for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-//      if (o->selected && o->is_widget()) {
-//        Fl_Widget_Type* q = (Fl_Widget_Type*)o;
-//        q->o->when(n|(q->o->when()&~FL_WHEN_NOT_CHANGED));
-//        mod = 1;
-//      }
-//    }
-//    if (mod) set_modflag(1);
-//  }
-}
-
 uchar Fl_Widget_Type::resizable() const {
-  if (is_window()) return ((Fl_Window*)o)->resizable() != 0;
+  if (is_a(ID_Window)) return ((Fl_Window*)o)->resizable() != 0;
   Fl_Group* p = (Fl_Group*)o->parent();
   if (p) return p->resizable() == o;
   else return 0;
@@ -1203,14 +1185,14 @@ uchar Fl_Widget_Type::resizable() const {
 void Fl_Widget_Type::resizable(uchar v) {
   if (v) {
     if (resizable()) return;
-    if (is_window()) ((Fl_Window*)o)->resizable(o);
+    if (is_a(ID_Window)) ((Fl_Window*)o)->resizable(o);
     else {
       Fl_Group* p = (Fl_Group*)o->parent();
       if (p) p->resizable(o);
     }
   } else {
     if (!resizable()) return;
-    if (is_window()) {
+    if (is_a(ID_Window)) {
       ((Fl_Window*)o)->resizable(0);
     } else {
       Fl_Group* p = (Fl_Group*)o->parent();
@@ -1221,7 +1203,7 @@ void Fl_Widget_Type::resizable(uchar v) {
 
 void resizable_cb(Fl_Light_Button* i,void* v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;}
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;}
     if (numselected > 1) {i->deactivate(); return;}
     i->activate();
     i->value(current_widget->resizable());
@@ -1235,21 +1217,21 @@ void resizable_cb(Fl_Light_Button* i,void* v) {
 void hotspot_cb(Fl_Light_Button* i,void* v) {
   if (v == LOAD) {
     if (numselected > 1) {i->deactivate(); return;}
-    if (current_widget->is_menu_item()) i->label("divider");
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) i->label("divider");
     else i->label("hotspot");
     i->activate();
     i->value(current_widget->hotspot());
   } else {
     undo_checkpoint();
     current_widget->hotspot(i->value());
-    if (current_widget->is_menu_item()) {
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {
       current_widget->redraw();
       return;
     }
     if (i->value()) {
       Fl_Type *p = current_widget->parent;
       if (!p || !p->is_widget()) return;
-      while (!p->is_window()) p = p->parent;
+      while (!p->is_a(Fl_Type::ID_Window)) p = p->parent;
       for (Fl_Type *o = p->next; o && o->level > p->level; o = o->next) {
         if (o->is_widget() && o != current_widget)
           ((Fl_Widget_Type*)o)->hotspot(0);
@@ -1262,7 +1244,7 @@ void hotspot_cb(Fl_Light_Button* i,void* v) {
 void visible_cb(Fl_Light_Button* i, void* v) {
   if (v == LOAD) {
     i->value(current_widget->o->visible());
-    if (current_widget->is_window()) i->deactivate();
+    if (current_widget->is_a(Fl_Type::ID_Window)) i->deactivate();
     else i->activate();
   } else {
     int mod = 0;
@@ -1277,9 +1259,9 @@ void visible_cb(Fl_Light_Button* i, void* v) {
         n ? q->o->show() : q->o->hide();
         q->redraw();
         if (n && q->parent && q->parent->type_name()) {
-          if (q->parent->id() == Fl_Type::ID_Tabs) {
+          if (q->parent->is_a(Fl_Type::ID_Tabs)) {
             ((Fl_Tabs *)q->o->parent())->value(q->o);
-          } else if (q->parent->id() == Fl_Type::ID_Wizard) {
+          } else if (q->parent->is_a(Fl_Type::ID_Wizard)) {
             ((Fl_Wizard *)q->o->parent())->value(q->o);
           }
         }
@@ -1295,7 +1277,7 @@ void visible_cb(Fl_Light_Button* i, void* v) {
 void active_cb(Fl_Light_Button* i, void* v) {
   if (v == LOAD) {
     i->value(current_widget->o->active());
-    if (current_widget->is_window()) i->deactivate();
+    if (current_widget->is_a(Fl_Type::ID_Window)) i->deactivate();
     else i->activate();
   } else {
     int mod = 0;
@@ -1438,7 +1420,7 @@ void color_common(Fl_Color c) {
     if (o->selected && o->is_widget()) {
       Fl_Widget_Type* q = (Fl_Widget_Type*)o;
       q->o->color(c); q->o->redraw();
-      if (q->parent && (q->parent->id() == Fl_Type::ID_Tabs)) {
+      if (q->parent && q->parent->is_a(Fl_Type::ID_Tabs)) {
         if (q->o->parent()) q->o->parent()->redraw();
       }
       mod = 1;
@@ -1450,7 +1432,7 @@ void color_common(Fl_Color c) {
 void color_cb(Fl_Button* i, void *v) {
   Fl_Color c = current_widget->o->color();
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
   } else {
     Fl_Color d = fl_show_colormap(c);
     if (d == c) return;
@@ -1463,7 +1445,7 @@ void color_cb(Fl_Button* i, void *v) {
 void color_menu_cb(Fl_Menu_Button* i, void *v) {
   Fl_Color c = current_widget->o->color();
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
   } else {
     Fl_Color d = (Fl_Color)(i->mvalue()->argument());
     if (d == c) return;
@@ -1488,7 +1470,7 @@ void color2_common(Fl_Color c) {
 void color2_cb(Fl_Button* i, void *v) {
   Fl_Color c = current_widget->o->selection_color();
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
   } else {
     Fl_Color d = fl_show_colormap(c);
     if (d == c) return;
@@ -1501,7 +1483,7 @@ void color2_cb(Fl_Button* i, void *v) {
 void color2_menu_cb(Fl_Menu_Button* i, void *v) {
   Fl_Color c = current_widget->o->selection_color();
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
   } else {
     Fl_Color d = (Fl_Color)(i->mvalue()->argument());
     if (d == c) return;
@@ -1573,7 +1555,7 @@ static Fl_Menu_Item alignmenu[] = {
 void align_cb(Fl_Button* i, void *v) {
   Fl_Align b = Fl_Align(fl_uintptr_t(i->user_data()));
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     i->value(current_widget->o->align() & b);
   } else {
     int mod = 0;
@@ -1611,7 +1593,7 @@ void align_cb(Fl_Button* i, void *v) {
 
 void align_position_cb(Fl_Choice *i, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     Fl_Menu_Item *mi = (Fl_Menu_Item*)i->menu();
     Fl_Align b = current_widget->o->align() & FL_ALIGN_POSITION_MASK;
     for (;mi->text;mi++) {
@@ -1641,7 +1623,7 @@ void align_position_cb(Fl_Choice *i, void *v) {
 
 void align_text_image_cb(Fl_Choice *i, void *v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     Fl_Menu_Item *mi = (Fl_Menu_Item*)i->menu();
     Fl_Align b = current_widget->o->align() & FL_ALIGN_IMAGE_MASK;
     for (;mi->text;mi++) {
@@ -1782,7 +1764,7 @@ void v_input_cb(Fl_Input* i, void* v) {
 
 void subclass_cb(Fl_Input* i, void* v) {
   if (v == LOAD) {
-    if (current_widget->is_menu_item()) {i->deactivate(); return;} else i->activate();
+    if (current_widget->is_a(Fl_Type::ID_Menu_Item)) {i->deactivate(); return;} else i->activate();
     i->value(current_widget->subclass());
   } else {
     int mod = 0;
@@ -1906,14 +1888,14 @@ void textcolor_menu_cb(Fl_Menu_Button* i, void* v) {
 
 void min_w_cb(Fl_Value_Input* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) return;
+    if (!current_widget->is_a(Fl_Type::ID_Window)) return;
     i->value(((Fl_Window_Type*)current_widget)->sr_min_w);
   } else {
     int mod = 0;
     undo_checkpoint();
     int n = (int)i->value();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         ((Fl_Window_Type*)current_widget)->sr_min_w = n;
         mod = 1;
       }
@@ -1924,14 +1906,14 @@ void min_w_cb(Fl_Value_Input* i, void* v) {
 
 void min_h_cb(Fl_Value_Input* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) return;
+    if (!current_widget->is_a(Fl_Type::ID_Window)) return;
     i->value(((Fl_Window_Type*)current_widget)->sr_min_h);
   } else {
     int mod = 0;
     undo_checkpoint();
     int n = (int)i->value();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         ((Fl_Window_Type*)current_widget)->sr_min_h = n;
         mod = 1;
       }
@@ -1942,14 +1924,14 @@ void min_h_cb(Fl_Value_Input* i, void* v) {
 
 void max_w_cb(Fl_Value_Input* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) return;
+    if (!current_widget->is_a(Fl_Type::ID_Window)) return;
     i->value(((Fl_Window_Type*)current_widget)->sr_max_w);
   } else {
     int mod = 0;
     undo_checkpoint();
     int n = (int)i->value();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         ((Fl_Window_Type*)current_widget)->sr_max_w = n;
         mod = 1;
       }
@@ -1960,14 +1942,14 @@ void max_w_cb(Fl_Value_Input* i, void* v) {
 
 void max_h_cb(Fl_Value_Input* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) return;
+    if (!current_widget->is_a(Fl_Type::ID_Window)) return;
     i->value(((Fl_Window_Type*)current_widget)->sr_max_h);
   } else {
     int mod = 0;
     undo_checkpoint();
     int n = (int)i->value();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         ((Fl_Window_Type*)current_widget)->sr_max_h = n;
         mod = 1;
       }
@@ -1982,7 +1964,7 @@ void set_min_size_cb(Fl_Button*, void* v) {
     int mod = 0;
     undo_checkpoint();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         Fl_Window_Type *win = (Fl_Window_Type*)current_widget;
         win->sr_min_w = win->o->w();
         win->sr_min_h = win->o->h();
@@ -2000,7 +1982,7 @@ void set_max_size_cb(Fl_Button*, void* v) {
     int mod = 0;
     undo_checkpoint();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         Fl_Window_Type *win = (Fl_Window_Type*)current_widget;
         win->sr_max_w = win->o->w();
         win->sr_max_h = win->o->h();
@@ -2162,7 +2144,7 @@ void value_cb(Fl_Value_Input* i, void* v) {
           mod = 1;
         } else if (q->is_button()) {
           ((Fl_Button*)(q->o))->value(n != 0);
-          if (q->is_menu_item()) q->redraw();
+          if (q->is_a(Fl_Type::ID_Menu_Item)) q->redraw();
           mod = 1;
         } else if (q->is_a(Fl_Type::ID_Spinner)) {
           ((Fl_Spinner*)(q->o))->value(n);
@@ -2179,9 +2161,9 @@ void value_cb(Fl_Value_Input* i, void* v) {
 
 void values_group_cb(Fl_Group* g, void* v) {
   if (v == LOAD) {
-    if (current_widget->is_flex()) {
+    if (current_widget->is_a(Fl_Type::ID_Flex)) {
       g->hide();
-    } else if (current_widget->is_window()) {
+    } else if (current_widget->is_a(Fl_Type::ID_Window)) {
       g->hide();
     } else {
       g->show();
@@ -2192,7 +2174,7 @@ void values_group_cb(Fl_Group* g, void* v) {
 
 void flex_margin_group_cb(Fl_Group* g, void* v) {
   if (v == LOAD) {
-    if (current_widget->is_flex()) {
+    if (current_widget->is_a(Fl_Type::ID_Flex)) {
       g->show();
     } else {
       g->hide();
@@ -2203,7 +2185,7 @@ void flex_margin_group_cb(Fl_Group* g, void* v) {
 
 void size_range_group_cb(Fl_Group* g, void* v) {
   if (v == LOAD) {
-    if (current_widget->is_window()) {
+    if (current_widget->is_a(Fl_Type::ID_Window)) {
       g->show();
     } else {
       g->hide();
@@ -2217,14 +2199,14 @@ static void flex_margin_cb(Fl_Value_Input* i, void* v,
                            void (*load_margin)(Fl_Flex*,Fl_Value_Input*),
                            int (*update_margin)(Fl_Flex*,int)) {
   if (v == LOAD) {
-    if (current_widget->is_flex()) {
+    if (current_widget->is_a(Fl_Type::ID_Flex)) {
       load_margin((Fl_Flex*)current_widget->o, i);
     }
   } else {
     int mod = 0;
     int new_value = (int)i->value();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_flex()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Flex)) {
         Fl_Flex_Type* q = (Fl_Flex_Type*)o;
         Fl_Flex* w = (Fl_Flex*)q->o;
         if (update_margin(w, new_value)) {
@@ -2481,7 +2463,7 @@ void subtype_cb(Fl_Choice* i, void* v) {
         if (q->subtypes()==m) {
           if (q->is_a(Fl_Type::ID_Spinner))
             ((Fl_Spinner*)q->o)->type(n);
-          else if (q->is_flex())
+          else if (q->is_a(Fl_Type::ID_Flex))
             ((Fl_Flex_Type*)q)->change_subtype_to(n);
           else
             q->o->type(n);
@@ -2568,7 +2550,7 @@ void live_mode_cb(Fl_Button*o,void *) {
         live_window->resizable(live_widget);
         live_window->set_modal(); // block all other UI
         live_window->callback(leave_live_mode_cb);
-        if (current_widget->is_window()) {
+        if (current_widget->is_a(Fl_Type::ID_Window)) {
           Fl_Window_Type *w = (Fl_Window_Type*)current_widget;
           int mw = w->sr_min_w; if (mw>0) mw += 20;
           int mh = w->sr_min_h; if (mh>0) mh += 55;
@@ -2811,7 +2793,7 @@ void Fl_Widget_Type::write_static(Fd_Code_Writer& f) {
       Fl_Type *q = 0;
       for (Fl_Type* p = parent; p && p->is_widget(); q = p, p = p->parent)
         f.write_c("->parent()");
-      if (!q || (q->id() != Fl_Type::ID_Widget_Class))
+      if (!q || !q->is_a(Fl_Type::ID_Widget_Class))
         f.write_c("->user_data()");
       f.write_c("))->%s_i(o,v);\n}\n", cn);
     }
@@ -2843,7 +2825,7 @@ void Fl_Widget_Type::write_code1(Fd_Code_Writer& f) {
     f.write_h("%sstatic void %s(%s*, %s);\n", f.indent(1), cn, t, ut);
   }
   // figure out if local variable will be used (prevent compiler warnings):
-  int wused = !name() && is_window();
+  int wused = !name() && is_a(ID_Window);
   const char *ptr;
 
   f.varused = wused;
@@ -2904,7 +2886,7 @@ void Fl_Widget_Type::write_code1(Fd_Code_Writer& f) {
   write_comment_inline_c(f);
   if (f.varused) f.write_c("%s* o = ", t);
   if (name()) f.write_c("%s = ", name());
-  if (is_window()) {
+  if (is_a(ID_Window)) {
     // Handle special case where user is faking a Fl_Group type as a window,
     // there is no 2-argument constructor in that case:
     if (!strstr(t, "Window"))
@@ -3010,7 +2992,7 @@ void Fl_Widget_Type::write_widget_code(Fd_Code_Writer& f) {
 
   if (is_a(Fl_Type::ID_Spinner) && ((Fl_Spinner*)o)->type() != ((Fl_Spinner*)tplate)->type())
     f.write_c("%s%s->type(%d);\n", f.indent(), var, ((Fl_Spinner*)o)->type());
-  else if (o->type() != tplate->type() && !is_window())
+  else if (o->type() != tplate->type() && !is_a(ID_Window))
     f.write_c("%s%s->type(%d);\n", f.indent(), var, o->type());
   if (o->box() != tplate->box() || subclass())
     f.write_c("%s%s->box(FL_%s);\n", f.indent(), var, boxname(o->box()));
@@ -3037,7 +3019,7 @@ void Fl_Widget_Type::write_widget_code(Fd_Code_Writer& f) {
     if (b->down_box()) f.write_c("%s%s->down_box(FL_%s);\n", f.indent(), var,
                                boxname(b->down_box()));
     if (b->value()) f.write_c("%s%s->value(1);\n", f.indent(), var);
-  } else if (id() == Fl_Type::ID_Input_Choice) {
+  } else if (is_a(Fl_Type::ID_Input_Choice)) {
     Fl_Input_Choice* b = (Fl_Input_Choice*)o;
     if (b->down_box()) f.write_c("%s%s->down_box(FL_%s);\n", f.indent(), var,
                                boxname(b->down_box()));
@@ -3134,7 +3116,7 @@ void Fl_Widget_Type::write_widget_code(Fd_Code_Writer& f) {
   if (hotspot()) {
     if (is_class())
       f.write_c("%shotspot(%s);\n", f.indent(), var);
-    else if (is_window())
+    else if (is_a(ID_Window))
       f.write_c("%s%s->hotspot(%s);\n", f.indent(), var, var);
     else
       f.write_c("%s%s->window()->hotspot(%s);\n", f.indent(), var, var);
@@ -3189,7 +3171,7 @@ void Fl_Widget_Type::write_properties(Fd_Project_Writer &f) {
   if (is_a(Fl_Type::ID_Spinner) && ((Fl_Spinner*)o)->type() != ((Fl_Spinner*)tplate)->type()) {
     f.write_string("type");
     f.write_word(item_name(subtypes(), ((Fl_Spinner*)o)->type()));
-  } else if (subtypes() && (o->type() != tplate->type() || is_window())) {
+  } else if (subtypes() && (o->type() != tplate->type() || is_a(ID_Window))) {
     f.write_string("type");
     f.write_word(item_name(subtypes(), o->type()));
   }
@@ -3213,7 +3195,7 @@ void Fl_Widget_Type::write_properties(Fd_Project_Writer &f) {
       f.write_string("down_box"); f.write_word(boxname(b->down_box()));}
     if (b->shortcut()) f.write_string("shortcut 0x%x", b->shortcut());
     if (b->value()) f.write_string("value 1");
-  } else if (id() == Fl_Type::ID_Input_Choice) {
+  } else if (is_a(Fl_Type::ID_Input_Choice)) {
     Fl_Input_Choice* b = (Fl_Input_Choice*)o;
     if (b->down_box()) {
       f.write_string("down_box"); f.write_word(boxname(b->down_box()));}
@@ -3270,7 +3252,7 @@ void Fl_Widget_Type::write_properties(Fd_Project_Writer &f) {
   if (!o->visible() && !override_visible_) f.write_string("hide");
   if (!o->active()) f.write_string("deactivate");
   if (resizable()) f.write_string("resizable");
-  if (hotspot()) f.write_string(is_menu_item() ? "divider" : "hotspot");
+  if (hotspot()) f.write_string(is_a(ID_Menu_Item) ? "divider" : "hotspot");
   for (int n=0; n < NUM_EXTRA_CODE; n++) if (extra_code(n)) {
     f.write_indent(level+1);
     f.write_string("code%d",n);
@@ -3345,7 +3327,7 @@ void Fl_Widget_Type::read_property(Fd_Project_Reader &f, const char *c) {
       if (x == ZERO_ENTRY) x = 0;
       ((Fl_Button*)o)->down_box((Fl_Boxtype)x);
     }
-  } else if ((id() == Fl_Type::ID_Input_Choice) && !strcmp(c,"down_box")) {
+  } else if (is_a(Fl_Type::ID_Input_Choice) && !strcmp(c,"down_box")) {
     const char* value = f.read_word();
     if ((x = boxnumber(value))) {
       if (x == ZERO_ENTRY) x = 0;
@@ -3478,7 +3460,7 @@ int Fl_Widget_Type::read_fdesign(const char* propname, const char* value) {
     if (sscanf(value,"%f %f %f %f",&x,&y,&w,&h) == 4) {
       if (fdesign_flip) {
         Fl_Type *p;
-        for (p = parent; p && !p->is_window(); p = p->parent) {/*empty*/}
+        for (p = parent; p && !p->is_a(ID_Window); p = p->parent) {/*empty*/}
         if (p && p->is_widget()) y = ((Fl_Widget_Type*)p)->o->h()-(y+h);
       }
       x += pasteoffset;
diff --git a/fluid/Fl_Widget_Type.h b/fluid/Fl_Widget_Type.h
index 91a9f9856..f2ce8ba88 100644
--- a/fluid/Fl_Widget_Type.h
+++ b/fluid/Fl_Widget_Type.h
@@ -105,8 +105,9 @@ public:
   virtual Fl_Menu_Item *subtypes();
 
   ID id() const FL_OVERRIDE { return ID_Widget_; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Widget_) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Widget_) ? true : super::is_a(inID); }
   int is_widget() const FL_OVERRIDE;
+  int is_true_widget() const FL_OVERRIDE { return 1; }
   int is_public() const FL_OVERRIDE;
 
   void write_properties(Fd_Project_Writer &f) FL_OVERRIDE;
diff --git a/fluid/Fl_Window_Type.cxx b/fluid/Fl_Window_Type.cxx
index fcfc8d7ae..236a736a8 100644
--- a/fluid/Fl_Window_Type.cxx
+++ b/fluid/Fl_Window_Type.cxx
@@ -316,7 +316,7 @@ void Fl_Window_Type::ideal_size(int &w, int &h) {
 
 void modal_cb(Fl_Light_Button* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) {i->hide(); return;}
+    if (!current_widget->is_a(Fl_Type::ID_Window)) {i->hide(); return;}
     i->show();
     i->value(((Fl_Window_Type *)current_widget)->modal);
   } else {
@@ -328,7 +328,7 @@ void modal_cb(Fl_Light_Button* i, void* v) {
 
 void non_modal_cb(Fl_Light_Button* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) {i->hide(); return;}
+    if (!current_widget->is_a(Fl_Type::ID_Window)) {i->hide(); return;}
     i->show();
     i->value(((Fl_Window_Type *)current_widget)->non_modal);
   } else {
@@ -340,7 +340,7 @@ void non_modal_cb(Fl_Light_Button* i, void* v) {
 
 void border_cb(Fl_Light_Button* i, void* v) {
   if (v == LOAD) {
-    if (!current_widget->is_window()) {i->hide(); return;}
+    if (!current_widget->is_a(Fl_Type::ID_Window)) {i->hide(); return;}
     i->show();
     i->value(((Fl_Window*)(current_widget->o))->border());
   } else {
@@ -352,7 +352,7 @@ void border_cb(Fl_Light_Button* i, void* v) {
 
 void xclass_cb(Fl_Input* i, void* v) {
   if (v == LOAD) {
-    if (current_widget->is_window()) {
+    if (current_widget->is_a(Fl_Type::ID_Window)) {
       i->show();
       i->parent()->show();
       i->value(((Fl_Window_Type *)current_widget)->xclass);
@@ -364,7 +364,7 @@ void xclass_cb(Fl_Input* i, void* v) {
     int mod = 0;
     undo_checkpoint();
     for (Fl_Type *o = Fl_Type::first; o; o = o->next) {
-      if (o->selected && o->is_window()) {
+      if (o->selected && o->is_a(Fl_Type::ID_Window)) {
         mod = 1;
         Fl_Window_Type *wt = (Fl_Window_Type *)o;
         storestring(i->value(), wt->xclass);
@@ -419,7 +419,7 @@ void Fl_Window_Type::newdx() {
   if (show_guides && (drag & (FD_DRAG|FD_TOP|FD_LEFT|FD_BOTTOM|FD_RIGHT))) {
     Fl_Type *selection = 0L; // special power for the first selected widget
     for (Fl_Type *q=next; q && q->level>level; q = q->next) {
-      if (q->selected && q->is_widget() && !q->is_menu_item()) {
+      if (q->selected && q->is_true_widget()) {
         selection = q;
         break;
       }
@@ -509,7 +509,7 @@ void fd_hatch(int x, int y, int w, int h, int size=6, int offset=0, int pad=3) {
  */
 void Fl_Window_Type::draw_out_of_bounds(Fl_Widget_Type *group, int x, int y, int w, int h) {
   for (Fl_Type *p = group->next; p && p->level>group->level; p = p->next) {
-    if (p->level == group->level+1 && p->is_widget() && !p->is_menu_item()) {
+    if (p->level == group->level+1 && p->is_true_widget()) {
       Fl_Widget *o = ((Fl_Widget_Type*)p)->o;
       if (o->x() < x) fd_hatch(o->x(), o->y(), x-o->x(), o->h());
       if (o->y() < y) fd_hatch(o->x(), o->y(), o->w(), y-o->y());
@@ -528,7 +528,7 @@ void Fl_Window_Type::draw_out_of_bounds() {
   draw_out_of_bounds(this, 0, 0, o->w(), o->h());
   for (Fl_Type *q=next; q && q->level>level; q = q->next) {
     // don't do this for Fl_Scroll (which we currently can't handle in FLUID anyway)
-    if (q->is_group() && !q->is_scroll()) {
+    if (q->is_group() && !q->is_a(ID_Scroll)) {
       Fl_Widget_Type *w = (Fl_Widget_Type*)q;
       draw_out_of_bounds(w, w->o->x(), w->o->y(), w->o->w(), w->o->h());
     }
@@ -544,14 +544,14 @@ void Fl_Window_Type::draw_overlaps() {
   // loop through all widgets in this window
   for (Fl_Type *q=next; q && q->level>level; q = q->next) {
     // is it a valid widget
-    if (q->is_widget() && !q->is_menu_item()) {
+    if (q->is_true_widget()) {
       Fl_Widget_Type *w = (Fl_Widget_Type*)q;
       // is the widget visible
       if (w->o->visible()) {
         int x = w->o->x(), y = w->o->y();
         int r = x + w->o->w(), b = y + w->o->h();
         for (Fl_Type *p=q->next; p && p->level>=q->level; p = p->next) {
-          if (p->level==q->level && p->is_widget() && !p->is_menu_item()) {
+          if (p->level==q->level && p->is_true_widget()) {
             Fl_Widget_Type *wp = (Fl_Widget_Type*)p;
             if (wp->o->visible()) {
               int px = fd_max(x, wp->o->x());
@@ -577,7 +577,7 @@ void Fl_Window_Type::draw_overlay() {
     bx = o->w(); by = o->h(); br = 0; bt = 0;
     numselected = 0;
     for (Fl_Type *q=next; q && q->level>level; q=q->next)
-      if (q->selected && q->is_widget() && !q->is_menu_item()) {
+      if (q->selected && q->is_true_widget()) {
         numselected++;
         Fl_Widget_Type* myo = (Fl_Widget_Type*)q;
         if (myo->o->x() < bx) bx = myo->o->x();
@@ -609,7 +609,7 @@ void Fl_Window_Type::draw_overlay() {
   mybx = mysx = o->w(); myby = mysy = o->h(); mybr = mysr = 0; mybt = myst = 0;
   Fl_Type *selection = 0L; // special power for the first selected widget
   for (Fl_Type *q=next; q && q->level>level; q = q->next)
-    if (q->selected && q->is_widget() && !q->is_menu_item()) {
+    if (q->selected && q->is_true_widget()) {
       if (!selection) selection = q;
       Fl_Widget_Type* myo = (Fl_Widget_Type*)q;
       int x,y,r,t;
@@ -694,24 +694,28 @@ void Fl_Window_Type::fix_overlay() {
 
 // check if we must redraw any parent of tabs/wizard type
 void check_redraw_corresponding_parent(Fl_Type *s) {
-    Fl_Widget_Type * prev_parent = 0;
-    if( !s || !s->selected || !s->is_widget()) return;
-    for (Fl_Type *i=s; i && i->parent; i=i->parent) {
-        if (i->is_group() && prev_parent &&
-            ( (i->id() == Fl_Type::ID_Tabs) ||
-              (i->id() == Fl_Type::ID_Wizard))) {
-             ((Fl_Tabs*)((Fl_Widget_Type*)i)->o)->value(prev_parent->o);
-             return;
-        }
-        if (i->is_group() && s->is_widget())
-            prev_parent = (Fl_Widget_Type*)i;
+  Fl_Widget_Type * prev_parent = 0;
+  if( !s || !s->selected || !s->is_widget()) return;
+  for (Fl_Type *i=s; i && i->parent; i=i->parent) {
+    if (i->is_group() && prev_parent) {
+      if (i->is_a(Fl_Type::ID_Tabs)) {
+        ((Fl_Tabs*)((Fl_Widget_Type*)i)->o)->value(prev_parent->o);
+        return;
+      }
+      if (i->is_a(Fl_Type::ID_Wizard)) {
+        ((Fl_Wizard*)((Fl_Widget_Type*)i)->o)->value(prev_parent->o);
+        return;
+      }
     }
+    if (i->is_group() && s->is_widget())
+      prev_parent = (Fl_Widget_Type*)i;
+  }
 }
 
 // do that for every window (when selected set changes):
 void redraw_overlays() {
   for (Fl_Type *o=Fl_Type::first; o; o=o->next)
-    if (o->is_window()) ((Fl_Window_Type*)o)->fix_overlay();
+    if (o->is_a(Fl_Type::ID_Window)) ((Fl_Window_Type*)o)->fix_overlay();
 }
 
 void toggle_overlays(Fl_Widget *,void *) {
@@ -726,7 +730,7 @@ void toggle_overlays(Fl_Widget *,void *) {
   }
 
   for (Fl_Type *o=Fl_Type::first; o; o=o->next)
-    if (o->is_window()) {
+    if (o->is_a(Fl_Type::ID_Window)) {
       Fl_Widget_Type* w = (Fl_Widget_Type*)o;
       ((Overlay_Window*)(w->o))->redraw_overlay();
     }
@@ -749,7 +753,7 @@ void toggle_guides(Fl_Widget *,void *) {
     guides_button->value(show_guides);
 
   for (Fl_Type *o=Fl_Type::first; o; o=o->next) {
-    if (o->is_window()) {
+    if (o->is_a(Fl_Type::ID_Window)) {
       Fl_Widget_Type* w = (Fl_Widget_Type*)o;
       ((Overlay_Window*)(w->o))->redraw_overlay();
     }
@@ -781,7 +785,7 @@ void toggle_restricted(Fl_Widget *,void *) {
     restricted_button->value(show_restricted);
 
   for (Fl_Type *o=Fl_Type::first; o; o=o->next) {
-    if (o->is_window()) {
+    if (o->is_a(Fl_Type::ID_Window)) {
       Fl_Widget_Type* w = (Fl_Widget_Type*)o;
       ((Overlay_Window*)(w->o))->redraw_overlay();
     }
@@ -811,7 +815,7 @@ void Fl_Window_Type::moveallchildren()
   undo_checkpoint();
   Fl_Type *i;
   for (i=next; i && i->level>level;) {
-    if (i->selected && i->is_widget() && !i->is_menu_item()) {
+    if (i->selected && i->is_true_widget()) {
       Fl_Widget_Type* myo = (Fl_Widget_Type*)i;
       int x,y,r,t,ow=myo->o->w(),oh=myo->o->h();
       newposition(myo,x,y,r,t);
@@ -834,7 +838,7 @@ void Fl_Window_Type::moveallchildren()
       // move all the children, whether selected or not:
       Fl_Type* p;
       for (p = myo->next; p && p->level>myo->level; p = p->next)
-        if (p->is_widget() && !p->is_menu_item() && !myo->is_flex()) {
+        if (p->is_true_widget() && !myo->is_a(ID_Flex)) {
           Fl_Widget_Type* myo2 = (Fl_Widget_Type*)p;
           int X,Y,R,T;
           newposition(myo2,X,Y,R,T);
@@ -992,7 +996,7 @@ int Fl_Window_Type::handle(int event) {
     // find the innermost item clicked on:
     selection = this;
     {for (Fl_Type* i=next; i && i->level>level; i=i->next)
-      if (i->is_widget() && !i->is_menu_item()) {
+      if (i->is_true_widget()) {
       Fl_Widget_Type* myo = (Fl_Widget_Type*)i;
       for (Fl_Widget *o1 = myo->o; o1; o1 = o1->parent())
         if (!o1->visible()) goto CONTINUE2;
@@ -1022,7 +1026,7 @@ int Fl_Window_Type::handle(int event) {
       } else {
         deselect();
         select(t, 1);
-        if (t->is_menu_item()) t->open();
+        if (t->is_a(ID_Menu_Item)) t->open();
       }
       selection = t;
       drag = 0;
@@ -1055,7 +1059,7 @@ int Fl_Window_Type::handle(int event) {
       if (!toggle) deselect(); else Fl::event_is_click(0);
       // select everything in box:
       for (Fl_Type*i=next; i&&i->level>level; i=i->next)
-        if (i->is_widget() && !i->is_menu_item()) {
+        if (i->is_true_widget()) {
         Fl_Widget_Type* myo = (Fl_Widget_Type*)i;
         for (Fl_Widget *o1 = myo->o; o1; o1 = o1->parent())
           if (!o1->visible()) goto CONTINUE;
@@ -1089,7 +1093,7 @@ int Fl_Window_Type::handle(int event) {
       if (Fl::event_state(FL_SHIFT)) backtab = 1;
       // find current child:
       Fl_Type *i = Fl_Type::current;
-      while (i && (!i->is_widget() || i->is_menu_item())) i = i->parent;
+      while (i && !i->is_true_widget()) i = i->parent;
       if (!i) return 0;
       Fl_Type *p = i->parent;
       while (p && p != this) p = p->parent;
@@ -1100,7 +1104,7 @@ int Fl_Window_Type::handle(int event) {
       for (;;) {
         i = backtab ? i->prev : i->next;
         if (!i || i->level <= level) {i = p; break;}
-        if (i->is_widget() && !i->is_menu_item()) break;
+        if (i->is_true_widget()) break;
       }
       deselect(); select(i,1);
       return 1;}
diff --git a/fluid/Fl_Window_Type.h b/fluid/Fl_Window_Type.h
index 7d4bc6474..a7a43eaf3 100644
--- a/fluid/Fl_Window_Type.h
+++ b/fluid/Fl_Window_Type.h
@@ -74,7 +74,7 @@ protected:
   int recalc;           // set by fix_overlay()
   void moveallchildren();
   ID id() const FL_OVERRIDE { return ID_Window; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Window) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Window) ? true : super::is_a(inID); }
   void open_();
 
 public:
@@ -115,7 +115,6 @@ public:
 
   int is_parent() const FL_OVERRIDE {return 1;}
   int is_group() const FL_OVERRIDE {return 1;}
-  int is_window() const FL_OVERRIDE {return 1;}
 
   Fl_Widget *enter_live_mode(int top=0) FL_OVERRIDE;
   void leave_live_mode() FL_OVERRIDE;
@@ -149,7 +148,7 @@ public:
   Fl_Type *make(Strategy strategy) FL_OVERRIDE;
   const char *type_name() FL_OVERRIDE {return "widget_class";}
   ID id() const FL_OVERRIDE { return ID_Widget_Class; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Widget_Class) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Widget_Class) ? true : super::is_a(inID); }
   int is_parent() const FL_OVERRIDE {return 1;}
   int is_code_block() const FL_OVERRIDE {return 1;}
   int is_decl_block() const FL_OVERRIDE {return 1;}
diff --git a/fluid/code.cxx b/fluid/code.cxx
index fe4a55dbd..452aa8b67 100644
--- a/fluid/code.cxx
+++ b/fluid/code.cxx
@@ -656,14 +656,14 @@ Fl_Type* Fd_Code_Writer::write_code(Fl_Type* p) {
   }
   // write all code that come before the children code
   // (but don't write the last comment until the very end)
-  if (!(p==Fl_Type::last && p->is_comment()))
+  if (!(p==Fl_Type::last && p->is_a(Fl_Type::ID_Comment)))
     p->write_code1(*this);
   // recursively write the code of all children
   Fl_Type* q;
   if (p->is_widget() && p->is_class()) {
     // Handle widget classes specially
     for (q = p->next; q && q->level > p->level;) {
-      if (q->id() != Fl_Type::ID_Function) q = write_code(q);
+      if (!q->is_a(Fl_Type::ID_Function)) q = write_code(q);
       else {
         int level = q->level;
         do {
@@ -676,7 +676,7 @@ Fl_Type* Fd_Code_Writer::write_code(Fl_Type* p) {
     p->write_code2(*this);
 
     for (q = p->next; q && q->level > p->level;) {
-      if (q->id() == Fl_Type::ID_Function) q = write_code(q);
+      if (q->is_a(Fl_Type::ID_Function)) q = write_code(q);
       else {
         int level = q->level;
         do {
@@ -733,7 +733,7 @@ int Fd_Code_Writer::write_code(const char *s, const char *t, bool to_sourceview)
   // if the first entry in the Type tree is a comment, then it is probably
   // a copyright notice. We print that before anything else in the file!
   Fl_Type* first_type = Fl_Type::first;
-  if (first_type && first_type->is_comment()) {
+  if (first_type && first_type->is_a(Fl_Type::ID_Comment)) {
     if (write_sourceview) {
       first_type->code_position = (int)ftell(code_file);
       first_type->header_position = (int)ftell(header_file);
@@ -850,7 +850,7 @@ int Fd_Code_Writer::write_code(const char *s, const char *t, bool to_sourceview)
   fprintf(header_file, "#endif\n");
 
   Fl_Type* last_type = Fl_Type::last;
-  if (last_type && last_type->is_comment()) {
+  if (last_type && last_type->is_a(Fl_Type::ID_Comment)) {
     if (write_sourceview) {
       last_type->code_position = (int)ftell(code_file);
       last_type->header_position = (int)ftell(header_file);
diff --git a/fluid/custom_widgets.cxx b/fluid/custom_widgets.cxx
index f3b374314..df4405196 100644
--- a/fluid/custom_widgets.cxx
+++ b/fluid/custom_widgets.cxx
@@ -111,7 +111,7 @@ int Widget_Bin_Window_Button::handle(int inEvent)
         Fl_Type *prototype = typename_to_prototype((char*)user_data());
         if (prototype) {
           Fl_Type *new_type = add_new_widget_from_user(prototype, kAddAfterCurrent);
-          if (new_type && new_type->is_window()) {
+          if (new_type && new_type->is_a(Fl_Type::ID_Window)) {
             Fl_Window_Type *new_window = (Fl_Window_Type*)new_type;
             Fl_Window *w = (Fl_Window *)new_window->o;
             w->position(Fl::event_x_root(), Fl::event_y_root());
diff --git a/fluid/factory.cxx b/fluid/factory.cxx
index 26ea50aef..d42941f73 100644
--- a/fluid/factory.cxx
+++ b/fluid/factory.cxx
@@ -108,7 +108,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Browser_Base_Type(); }
   ID id() const FL_OVERRIDE { return ID_Browser_; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Browser_) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Browser_) ? true : super::is_a(inID); }
 };
 
 static Fl_Browser_Base_Type Fl_Browser_Base_type;
@@ -141,7 +141,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Browser_Type(); }
   ID id() const FL_OVERRIDE { return ID_Browser; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Browser) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Browser) ? true : super::is_a(inID); }
 };
 
 static Fl_Browser_Type Fl_Browser_type;
@@ -174,7 +174,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Check_Browser_Type(); }
   ID id() const FL_OVERRIDE { return ID_Check_Browser; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Check_Browser) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Check_Browser) ? true : super::is_a(inID); }
 };
 
 static Fl_Check_Browser_Type Fl_Check_Browser_type;
@@ -200,7 +200,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_File_Browser_Type(); }
   ID id() const FL_OVERRIDE { return ID_File_Browser; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_File_Browser) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_File_Browser) ? true : super::is_a(inID); }
 };
 
 static Fl_File_Browser_Type Fl_File_Browser_type;
@@ -243,7 +243,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Tree_Type(); }
   ID id() const FL_OVERRIDE { return ID_Tree; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Tree) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Tree) ? true : super::is_a(inID); }
 };
 
 static Fl_Tree_Type Fl_Tree_type;
@@ -289,7 +289,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Help_View_Type(); }
   ID id() const FL_OVERRIDE { return ID_Help_View; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Help_View) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Help_View) ? true : super::is_a(inID); }
 };
 
 static Fl_Help_View_Type Fl_Help_View_type;
@@ -315,7 +315,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Valuator_Type(); }
   ID id() const FL_OVERRIDE { return ID_Valuator_; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Valuator_) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Valuator_) ? true : super::is_a(inID); }
 };
 
 static Fl_Valuator_Type Fl_Valuator_type;
@@ -361,7 +361,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Counter_Type(); }
   ID id() const FL_OVERRIDE { return ID_Counter; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Counter) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Counter) ? true : super::is_a(inID); }
 };
 
 static Fl_Counter_Type Fl_Counter_type;
@@ -388,7 +388,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Adjuster_Type(); }
   ID id() const FL_OVERRIDE { return ID_Adjuster; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Adjuster) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Adjuster) ? true : super::is_a(inID); }
 };
 
 static Fl_Adjuster_Type Fl_Adjuster_type;
@@ -422,7 +422,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Dial_Type(); }
   ID id() const FL_OVERRIDE { return ID_Dial; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Dial) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Dial) ? true : super::is_a(inID); }
 };
 static Fl_Dial_Type Fl_Dial_type;
 
@@ -455,7 +455,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Roller_Type(); }
   ID id() const FL_OVERRIDE { return ID_Roller; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Roller) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Roller) ? true : super::is_a(inID); }
 };
 
 static Fl_Roller_Type Fl_Roller_type;
@@ -495,7 +495,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Slider_Type(); }
   ID id() const FL_OVERRIDE { return ID_Slider; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Slider) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Slider) ? true : super::is_a(inID); }
 };
 
 static Fl_Slider_Type Fl_Slider_type;
@@ -524,7 +524,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Scrollbar_Type(); }
   ID id() const FL_OVERRIDE { return ID_Scrollbar; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Scrollbar) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Scrollbar) ? true : super::is_a(inID); }
 };
 static Fl_Scrollbar_Type Fl_Scrollbar_type;
 
@@ -556,7 +556,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Value_Slider_Type(); }
   ID id() const FL_OVERRIDE { return ID_Value_Slider; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Value_Slider) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Value_Slider) ? true : super::is_a(inID); }
 };
 
 static Fl_Value_Slider_Type Fl_Value_Slider_type;
@@ -595,7 +595,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Value_Input_Type(); }
   ID id() const FL_OVERRIDE { return ID_Value_Input; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Value_Input) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Value_Input) ? true : super::is_a(inID); }
 };
 
 static Fl_Value_Input_Type Fl_Value_Input_type;
@@ -634,7 +634,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Value_Output_Type(); }
   ID id() const FL_OVERRIDE { return ID_Value_Output; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Value_Output) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Value_Output) ? true : super::is_a(inID); }
 };
 
 static Fl_Value_Output_Type Fl_Value_Output_type;
@@ -690,7 +690,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Input_Type(); }
   ID id() const FL_OVERRIDE { return ID_Input; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Input) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Input) ? true : super::is_a(inID); }
   void copy_properties() FL_OVERRIDE {
     Fl_Widget_Type::copy_properties();
     Fl_Input_ *d = (Fl_Input_*)live_widget, *s = (Fl_Input_*)o;
@@ -727,7 +727,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_File_Input_Type(); }
   ID id() const FL_OVERRIDE { return ID_File_Input; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_File_Input) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_File_Input) ? true : super::is_a(inID); }
 };
 
 static Fl_File_Input_Type Fl_File_Input_type;
@@ -758,7 +758,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Output_Type(); }
   ID id() const FL_OVERRIDE { return ID_Output; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Output) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Output) ? true : super::is_a(inID); }
 };
 
 static Fl_Output_Type Fl_Output_type;
@@ -808,7 +808,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Text_Display_Type(); }
   ID id() const FL_OVERRIDE { return ID_Text_Display; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Text_Display) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Text_Display) ? true : super::is_a(inID); }
 };
 static Fl_Text_Display_Type Fl_Text_Display_type;
 
@@ -835,7 +835,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Text_Editor_Type(); }
   ID id() const FL_OVERRIDE { return ID_Text_Editor; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Text_Editor) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Text_Editor) ? true : super::is_a(inID); }
 };
 
 static Fl_Text_Editor_Type Fl_Text_Editor_type;
@@ -868,7 +868,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE {return new Fl_Simple_Terminal_Type();}
   ID id() const FL_OVERRIDE { return ID_Simple_Terminal; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Simple_Terminal) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Simple_Terminal) ? true : super::is_a(inID); }
 };
 
 static Fl_Simple_Terminal_Type Fl_Simple_Terminal_type;
@@ -898,7 +898,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Box_Type(); }
   ID id() const FL_OVERRIDE { return ID_Box; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Box) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Box) ? true : super::is_a(inID); }
 };
 
 static Fl_Box_Type Fl_Box_type;
@@ -925,7 +925,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Clock_Type(); }
   ID id() const FL_OVERRIDE { return ID_Clock; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Clock) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Clock) ? true : super::is_a(inID); }
 };
 
 static Fl_Clock_Type Fl_Clock_type;
@@ -956,7 +956,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Progress_Type(); }
   ID id() const FL_OVERRIDE { return ID_Progress; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Progress) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Progress) ? true : super::is_a(inID); }
 };
 
 static Fl_Progress_Type Fl_Progress_type;
@@ -1002,7 +1002,7 @@ public:
   }
   Fl_Widget_Type *_make() FL_OVERRIDE { return new Fl_Spinner_Type(); }
   ID id() const FL_OVERRIDE { return ID_Spinner; }
-  bool is_a(ID inID) FL_OVERRIDE { return (inID==ID_Spinner) ? true : super::is_a(inID); }
+  bool is_a(ID inID) const FL_OVERRIDE { return (inID==ID_Spinner) ? true : super::is_a(inID); }
 };
 
 static Fl_Spinner_Type Fl_Spinner_type;
@@ -1149,7 +1149,7 @@ Fl_Type *add_new_widget_from_user(Fl_Type *inPrototype, Strategy strategy) {
   undo_suspend();
   Fl_Type *t = ((Fl_Type*)inPrototype)->make(strategy);
   if (t) {
-    if (t->is_widget() && !t->is_window())
+    if (t->is_widget() && !t->is_a(Fl_Type::ID_Window))
     {
       Fl_Widget_Type *wt = (Fl_Widget_Type *)t;
 
@@ -1168,7 +1168,7 @@ Fl_Type *add_new_widget_from_user(Fl_Type *inPrototype, Strategy strategy) {
       int w = 0, h = 0;
       wt->ideal_size(w, h);
 
-      if ((t->parent && t->parent->is_flex())) {
+      if ((t->parent && t->parent->is_a(Fl_Type::ID_Flex))) {
         // Do not resize or layout the widget. Flex will need the widget size.
       } else if (wt->is_a(Fl_Type::ID_Menu_Bar)) {
         // Move and resize the menubar across the top of the window...
@@ -1185,7 +1185,7 @@ Fl_Type *add_new_widget_from_user(Fl_Type *inPrototype, Strategy strategy) {
         }
       }
     }
-    if (t->is_window()) {
+    if (t->is_a(Fl_Type::ID_Window)) {
       int x = 0, y = 0, w = 480, h = 320;
       Fl_Window_Type *wt = (Fl_Window_Type *)t;
       wt->ideal_size(w, h);
diff --git a/fluid/fluid.cxx b/fluid/fluid.cxx
index 06afb7997..8ae89785d 100644
--- a/fluid/fluid.cxx
+++ b/fluid/fluid.cxx
@@ -626,7 +626,7 @@ void save_template_cb(Fl_Widget *, void *) {
 
   for (t = Fl_Type::first; t; t = t->next) {
     // Find the first window...
-    if (t->is_window()) break;
+    if (t->is_a(Fl_Type::ID_Window)) break;
   }
 
   if (!t) return;
@@ -1349,7 +1349,7 @@ void print_menu_cb(Fl_Widget *, void *) {
   Fl_Window *win;
 
   for (t = Fl_Type::first, num_windows = 0; t; t = t->next) {
-    if (t->is_window()) {
+    if (t->is_a(Fl_Type::ID_Window)) {
       windows[num_windows] = (Fl_Window_Type *)t;
       if (!((Fl_Window*)(windows[num_windows]->o))->shown()) continue;
       num_windows ++;
diff --git a/fluid/widget_browser.cxx b/fluid/widget_browser.cxx
index b9e6f68dd..b7f95ba62 100644
--- a/fluid/widget_browser.cxx
+++ b/fluid/widget_browser.cxx
@@ -345,11 +345,11 @@ void Widget_Browser::item_draw(void *v, int X, int Y, int, int) const {
   }
 
   if (   l->is_widget()
-      && !l->is_window()
+      && !l->is_a(Fl_Type::ID_Window)
       && ((Fl_Widget_Type*)l)->o
       && !((Fl_Widget_Type*)l)->o->visible()
-      && (!l->parent || (   (l->parent->id() != Fl_Type::ID_Tabs)
-                         && (l->parent->id() != Fl_Type::ID_Wizard) ) )
+      && (!l->parent || (   !l->parent->is_a(Fl_Type::ID_Tabs)
+                         && !l->parent->is_a(Fl_Type::ID_Wizard) ) )
       )
   {
     invisible_pixmap->draw(X - 17, Y);
diff --git a/test/checkers_pieces.fl b/test/checkers_pieces.fl
index 8cd09e9b5..abe2184ff 100644
--- a/test/checkers_pieces.fl
+++ b/test/checkers_pieces.fl
@@ -2,6 +2,11 @@
 version 1.0400
 header_name {.h}
 code_name {.cxx}
+snap {
+  ver 1
+  current_suite FLTK
+  current_preset 0
+}
 comment {//
 // Checkers images for the Fast Light Tool Kit (FLTK).
 //
diff --git a/test/mandelbrot_ui.fl b/test/mandelbrot_ui.fl
index 0c289e6f6..180a6fcb0 100644
--- a/test/mandelbrot_ui.fl
+++ b/test/mandelbrot_ui.fl
@@ -2,6 +2,11 @@
 version 1.0400
 header_name {.h}
 code_name {.cxx}
+snap {
+  ver 1
+  current_suite FLTK
+  current_preset 0
+}
 decl {\#include "mandelbrot.h"} {public local
 }
 
diff --git a/test/tabs.fl b/test/tabs.fl
index 35223501f..ec8d4871c 100644
--- a/test/tabs.fl
+++ b/test/tabs.fl
@@ -2,6 +2,11 @@
 version 1.0400
 header_name {.h}
 code_name {.cxx}
+snap {
+  ver 1
+  current_suite FLTK
+  current_preset 0
+}
 Function {} {open
 } {
   Fl_Window foo_window {