Hi Carlo,
the fix was only temporary. After about 20 minutes of working the screen was corrupted again. (Parallels on an external monitor in full screen).
My console (console.app) is being flooded with messages
standard 09:39:56.206890 +0200 WindowServer No matching context for device (0x7f991b7123b0) - disabling OpenGL
This only happens with the Display Link hub attached. Any connection?
Maybe the others can check if their console also exhibits the same behaviour?
Regards
Philip