I still can't solve this issue. I have checked all drivers and monitors, HDMI cables, settings everything I can think of. I have a laptop and two additional and identical monitors. It only ever occurs on the 2nd monitor. I'll try a VGA cable today, and a couple of other things I thought about last night.

What is odd is that if I adjust the offending window slightly everything appears correctly, then when you start using the tabs once again the problem returns???