- When the message filter would receive and process a mouse moved message,
if the message resulted in causing the deskbar to relocate or reorient
itself, it was possible for the expando view to become detached from
the looper. Consequently, if the intercepted mouse moved happened to have
come from the latter, when returning out of the filter the view would no
longer have a target looper, triggering a debugger condition in BLooper.
In order to prevent this situation, we now dispatch a message asking for
the layout change to occur asynchronously.