Hello there !

I just installed https://neon.kde.org
My problem is that when I open any program, everything around the window becomes black. When I drag the window around, the black part of the screen "erases" and shows my background image & widgets on the desktop or the program that's opened on the background. The black screen also disappears when I maximize or click outside the opened program. Sorry if this sounds vague but There's no way to describe it really.

Here are some screenshots of this:
http://imgur.com/PbOuHcq
http://imgur.com/UPuzE8W

I would love to get some feedback on this problem

UPDATE:

Never happened again after I rebooted. But this was strange.

BTW What's up with Discover ? Lacks software....

UPDATE:

It started happening again after playing a game of Insurgency. It's an OpenGL game if this matters.