K4in-5037

I found this issue after trying to get blurred decorations not knowing it was a bug, it may not be immediately noticeable because some windows can set explicitly its blur...

@Zren you were right, I had no borders set and didn't noticed the Left/Right/Bottom borders  Using `setBlurRegion(QRegion(0, 0, size().width(), size().height()));`  Applies blur to all sides. I've got that...

Thank you, I tried your fork and it works. Then for fun I tried to assign proper names and fix the mislabeled buttons, I'm putting here my process in case...