diff --git a/src/Fl.cxx b/src/Fl.cxx
index 61263b44d..bcf820410 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -113,7 +113,7 @@ unsigned char   Fl::options_[] = { 0, 0 };
 unsigned char   Fl::options_read_ = 0;
 
 
-Fl_Window *fl_xfocus;	// which window X thinks has focus
+Fl_Window *fl_xfocus = NULL;	// which window X thinks has focus
 Fl_Window *fl_xmousewin;// which window X thinks has FL_ENTER
 Fl_Window *Fl::grab_;	// most recent Fl::grab()
 Fl_Window *Fl::modal_;	// topmost modal() window
diff --git a/src/Fl_x.cxx b/src/Fl_x.cxx
index 7869791d7..c3f2ea2a3 100644
--- a/src/Fl_x.cxx
+++ b/src/Fl_x.cxx
@@ -2213,12 +2213,17 @@ void Fl_X::activate_window(Window w) {
   if (!ewmh_supported())
     return;
 
-  Fl_X *x = Fl_X::i(fl_xfocus);
-  if (!x)
-    return;
+  Window prev = 0;
+
+  if (fl_xfocus) {
+    Fl_X *x = Fl_X::i(fl_xfocus);
+    if (!x)
+      return;
+    prev = x->xid;
+  }
 
   send_wm_event(w, fl_NET_ACTIVE_WINDOW, 1 /* application */,
-                0 /* timestamp */, x->xid /* previously active window */);
+                0 /* timestamp */, prev /* previously active window */);
 }
 
 /* Change an existing window to fullscreen */