def drag_begin(self, widget, context):
surface = self.get_drag_surface()
if surface :
surface.set_device_offset(0, 0)
self.surface = surface
Gtk.drag_set_icon_surface(context, surface)
else:
Gtk.drag_set_icon_default(context)
self.stop_drag_check()
# TODO : implement selection cache ?
selection_cache = self.drag_create_selection_cache()
