From 005bfa42940f69d4bad9d4fc22dc64a694869137 Mon Sep 17 00:00:00 2001
From: Lauri Kasanen <cand@gmx.com>
Date: Fri, 5 Sep 2014 12:33:35 +0000
Subject: [PATCH] Fix cross-window focus throwing on X11, similar to the Mac
 case. STR #3129

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10276 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 FL/x.H       |  1 +
 src/Fl.cxx   | 11 +++++++++--
 src/Fl_x.cxx | 16 ++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/FL/x.H b/FL/x.H
index 37e361ffc..012b56405 100644
--- a/FL/x.H
+++ b/FL/x.H
@@ -160,6 +160,7 @@ public:
   static void x(Fl_Window* wi, int X) {wi->x(X);}
   static void y(Fl_Window* wi, int Y) {wi->y(Y);}
   static int ewmh_supported();
+  static void activate_window(Window w);
 };
 
 extern FL_EXPORT char fl_override_redirect; // hack into Fl_X::make_xid()
diff --git a/src/Fl.cxx b/src/Fl.cxx
index 714c8deee..61263b44d 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -922,10 +922,17 @@ void Fl::focus(Fl_Widget *o) {
 	if (fl_xfocus != win) {
 	  Fl_X *x = Fl_X::i(win);
 	  if (x) x->set_key_window();
-	  }
+	}
+#elif defined(USE_X11)
+	if (fl_xfocus != win) {
+	  Fl_X *x = Fl_X::i(win);
+	  win->show(); // Old WMs, XMapRaised
+	  // New WMs use the NETWM attribute:
+	  if (x) Fl_X::activate_window(x->xid);
+	}
 #endif
 	fl_xfocus = win;
-	}
+      }
     }
     // take focus from the old focused window
     fl_oldfocus = 0;
diff --git a/src/Fl_x.cxx b/src/Fl_x.cxx
index 67971b453..7869791d7 100644
--- a/src/Fl_x.cxx
+++ b/src/Fl_x.cxx
@@ -356,6 +356,7 @@ static Atom fl_NET_WM_STATE_FULLSCREEN;
 static Atom fl_NET_WM_FULLSCREEN_MONITORS;
 static Atom fl_NET_WORKAREA;
 static Atom fl_NET_WM_ICON;
+static Atom fl_NET_ACTIVE_WINDOW;
 
 /*
   X defines 32-bit-entities to have a format value of max. 32,
@@ -667,6 +668,7 @@ void fl_open_display(Display* d) {
   fl_NET_WM_FULLSCREEN_MONITORS = XInternAtom(d, "_NET_WM_FULLSCREEN_MONITORS", 0);
   fl_NET_WORKAREA       = XInternAtom(d, "_NET_WORKAREA",       0);
   fl_NET_WM_ICON        = XInternAtom(d, "_NET_WM_ICON",        0);
+  fl_NET_ACTIVE_WINDOW  = XInternAtom(d, "_NET_ACTIVE_WINDOW",  0);
 
   if (sizeof(Atom) < 4)
     atom_bits = sizeof(Atom) * 8;
@@ -2205,6 +2207,20 @@ int Fl_X::ewmh_supported() {
   return result;
 }
 
+extern Fl_Window *fl_xfocus;
+
+void Fl_X::activate_window(Window w) {
+  if (!ewmh_supported())
+    return;
+
+  Fl_X *x = Fl_X::i(fl_xfocus);
+  if (!x)
+    return;
+
+  send_wm_event(w, fl_NET_ACTIVE_WINDOW, 1 /* application */,
+                0 /* timestamp */, x->xid /* previously active window */);
+}
+
 /* Change an existing window to fullscreen */
 void Fl_Window::fullscreen_x() {
   if (Fl_X::ewmh_supported()) {