Description:
After hibernation, some application windows will only maximize to the left screen, regardless of where it was originally maximized.

So far I can only repeat this with Firefox. I'm unsure if this is more related to Firefox, or if it is an actual kwin issue. As an experiment, I switched the outputs on my graphics card so the screens were switched; this resulted in the exact same behaviour - maximize to left only.

Some games also have this issue, but it is more often than not, independent of any window manager or hibernation status. This is what leads me to look at kwin for this issue.

Reproducible: Always

Steps to Reproduce:
1. Maximize Firefox to right screen
2. Hibernate the PC
3. Wake

Actual Results:  
Firefox will now only maximize to the left screen

Expected Results:  
Firefox should maximize to any screen.