2 Replies
Brett Rockwood

Easiest way is to just put a partially transparent black box that covers the entire screen as the bottom item on the timeline of your selected layer. When you close that layer the black box closes with it (of course).

I suppose you could get fancy and do a screen shot of the base layer, put a blur on that and use it as the bottom item in your selected layer. That could be bothersome if you make any changes to the base layer as you have to make a new screen shot each time for your selected layer, otherwise it wouldn't look right.