[SOLVED] Bluescreen after login and kwinx11

[LearningLinuxDk]

I am experiencing this strange problem that after I log in, the screen turns blue. Does anyone know what it could be due to?

If I close kwin_x11 the blue disappears. What have I done? Or how do I fix it?

See it here:

https://youtu.be/8V-oT2Q0j4g

[LearningLinuxDk]

I fixed it by changing the Compositor, from OpenGl 2 to XRender