Actually, I have a bug I guess. Enabling the darken feature causes my Taskbar to overlap most right-click menus for Notification area programs as well as the Start Menu itself (in the case of the Start Menu, if I clcik on the Task Bar first and then click on the Start Menu, the Start Menu will stay on top.)
Disabling the darken feature fixes the problem. I keep my Taskbar on the left side of mt desktop, so it run the full height. You can imagine how bad that would be for obscuing menus.
I'm on Win7Ult with a Sapphire-branded 5770 Vidcard (Catalyst 10.12 installed). Below is a shot of the two situations I described: