Although action messages could lay around and have no effect when a their target messages are deleted, it'd be nice to have the action messages deleted automatically. A couple ideas:
ActionMessageManager listens for a broadcast that is sent whenever a delete happens, looks for action messages associated with the deleted message, deletes them.
ChannelSyncManager has a method for deleting a message and does the same work as in 1) above.
Although action messages could lay around and have no effect when a their target messages are deleted, it'd be nice to have the action messages deleted automatically. A couple ideas: