On X11, borderless windows will not show in the taskbar anymore (STR #933)

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@4492 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CHANGES

@@ -3,6 +3,8 @@ CHANGES IN FLTK 1.1.7
 	- Documentation fixes (STR #571, STR #648, STR #692, STR
 	  #730, STR #744, STR #745, STR #931, STR #942, STR #960,
 	  STR #969)
+	- Borderless windows will not show in the taskbar anymore
+	  on X11 (STR #933)
 	- Fixed event_text() field on FL_DND_* event on 
 	  OS X (STR #968)
 	- The fltk-config utility now supports "--cc" and "--cxx"

src/Fl_x.cxx

@@ -1141,6 +1141,14 @@ void Fl_X::make_xid(Fl_Window* win, XVisualInfo *visual, Colormap colormap)
       XSetTransientForHint(fl_display, xp->xid, fl_xid(wp));
       if (!wp->visible()) showit = 0; // guess that wm will not show it
     }
+   
+    // Make sure that borderless windows do not show in the task bar
+    if (!win->border()) {
+      Atom net_wm_state = XInternAtom (fl_display, "_NET_WM_STATE", 0);
+      Atom net_wm_state_skip_taskbar = XInternAtom (fl_display, "_NET_WM_STATE_SKIP_TASKBAR", 0);
+      XChangeProperty (fl_display, xp->xid, net_wm_state, XA_ATOM, 32, 
+          PropModeAppend, (unsigned char*) &net_wm_state_skip_taskbar, 1);
+    }
 
     // Make it receptive to DnD:
     long version = 4;