dnd: Notify about events during compositor grab from event filter
Not exactly a great solution to make the event filter even larger, but it works...
@carlosg this is the dnd issue I mentioned on the call yesterday.
Main commit:
Since the introduction of ClutterGrabs, MetaDnd now no longer gets notified about input events on the stage during grabs (for example while the alt-tab popup is shown) and thus can't move the grab feedback actor anymore.
To fix this, forward events to MetaDnD directly from meta_display_handle_event() when a ClutterGrab is in effect.