window-list: Stop monitoring drag operation if window disappears
If a user is in the middle of a drag of the window list when the window list gets destroyed, the drag monitor gets leaked.
Later when the drag motion is processed, this spew goes to the log
clutter_actor_contains: assertion 'CLUTTER_IS_ACTOR (self)' failed
This commit fixes the spew and the leak by ensuring any pending drag monitoring is disabled when the window list is destroyed.
Edited by Ray Strode