Very poor performance in the editor using multiple monitors

Trying to work today using just one monitor. I have only the main editor window open but I still get the same slow down and can’t use the editor at all. Even restarting the editor doesn’t help.

I’ve noticed it always happens when a tooltip is visible, but also it can occur randomly and then won’t stop. It almost always happens when a window separate to the main one is open.

This is a very serious issue for me and has massively affected my work. I’m even considering changing to mac or win 7 to see if it fixes the problem. Can someone at Epic pleeease look at this bug. It sounds like I’m not the only one experiencing it and it actually renders the engine unusable.