On both my 4500s (V8.08.12-MV16 ), I'm experiencing an intermittent issue with the VPX interface software. The status buttons (all of them for each device) and the red box that highlights the current device disappears. Fortunately, the field at the top of the screen still indicates the selected device, so there is a workaround.

At first I thought it only happened after a breaker was tripped, but that isn't the case. It happens randomly whenever I bring up the checklist screen. Sometimes it works correctly and sometimes it doesn't. I haven't been able to make it fail on demand yet.