Every clip goes into full screen when I double click on it.

I was chugging right along when I hit a key stroke and the next thing I know I'm seeing everything that's supposed to be in my source monitor in full screen mode. It cover the timeline monitor, the sequence, everything.For the record I'm on a MAC, Lion and I have a two CPU monitor setup and a matrox mxo2 that I use the HDMI connector to view on a 42 inch screen.

I found that, control and tilda key brings it back down to it's normal size but as soon as I try and mark an in, scroll, drag, whatever, it goes back into full screen mode. When I click on the timeline monitor no issues, when I play the sequence Its fine on the timeline monitor.

When I match frame, it brings it up but full screen. If I double click the clip in the sequence, same thing full screen.

Any Idea what's causing this?