Preview flicker

Having just updated (the offer of any performance improvement is too hard to resist) I'm being annoyed by a flicker when I start work on the next shot.

I think it shows the last adjustment to the previous photograph before showing the new one. It's really, really annoying, so is this a new bug, or is there a way to stop it happening???

On further checking, it seems to relate to the graduated and radial filters. If you have applied one and then, when you work on another shot, if you select the filter you get a brief flicker of the previous shot and where the filter was positioned. It only lasts for a moment, but I cannot believe I'm the only one to see it, or that they released the update with such an obvious flaw!

And why has the 'Exit' cross icon to close the program disappeared?????!!!!????