9c4908b44a
If we attach to a MetaWindow that disappears before the idle fires, we'll notice that we can't associate the window properly again and try to access data on the MetaWindow struct, which might crash. Install a weak ref that ties the lifetime of the idle to the lifetime of the MetaWindow. It seems every GTK+ app does this for some reason at startup. This is really unfortunate, since we'll have to create and destroy a new MetaWindow really quickly.