In Flash Player 11.2 and above:
1. Right-click to show context menu.
2. Click somewhere outside menu to hide it.
3. Every mouse event has "buttonPressed=true"
This will have many side effects, one of which is the ContextMenuEvent.MENU_SELECT event will not be triggered and therefore handling custom menus becomes impossible.
Is this is a known bug? Is there a workaround?
I haven't seen this come up before, but usually this forum deals with end user issues. I'd recommend hoping over to bugbase.adobe.com and entering a bug. We'll take a look and let you know what we find.