2.5

- after closing button (having used it), it sends empty mousemove for 
  invoking new modal handler on same button. Don't know better solution
  for now, at least this way WM handles everything. :)

- experiment: moved button handlers to area level, that way it respects
  handlers on higher hierarchical level, like moving area edges.
  Als interesting is that you can have a button active (texteditor) and
  use a similar button in other area.
  This can also be done on region level even.

On todo: proper notifier events for redraw! Don't want all areas to draw
on simple refreshes

source/blender/windowmanager/WM_api.h

@@ -75,6 +75,7 @@ void		WM_event_remove_handlers			(bContext *C, ListBase *handlers);
 
 void		WM_event_add_message(wmWindowManager *wm, void *customdata,
                                  short customdatafree);
+void		WM_event_add_mousemove(bContext *C);
 
 void		WM_event_add_notifier(wmWindowManager *wm, wmWindow *window,
 					int swinid, int type,