No graphic refresh without mouse movement in KDE Plasma

[Mika15]

Hi Everyone,

I have problems since weeks that I can't manage to solve, I don't know how to describe it exactly and how to find a way to solve it, so I ask you help.

Like I wrote in the title, my gentoo have KDE Plasma installed, everything working well before, and since some updates, the Windows manager doesn't refresh the screen if I don't move the mouse.
I mean that in a Flash video in fullscreen, the sound keep playing but the image doesn't move, if I move the mouse and don't stop to do it, the video is playing.

It also happens when I'm in Dolphin, if I move from a folder to another using keyboard directions keys, the highlighted folder is refreshed only when I move the mouse, the same if I delete something from the keyboard, I have to move the mouse to see the confirmation box.

So, is very painful, I will appreciate any kind of help to solve this problem.

Many thanks.