Reduced quality + Taskbar on fullscreen

[E_net4]

This is what happens(see picture). The guis get some pink artifacts and all textures have an awfully reduced quality.
The taskbar shows up on fullscreen, also.
Could someone help, please?

[Ad Bot]

[E_net4]

Bump. Please, give me a solution!

[Badspot]

Click on everything in the task bar, then alt tab back to Blockland. 

[E_net4]

Nope. It didn't work. 

[Packer]

Play in windowed mode? My friend had this problem but the only way to fix it was by changing the Display driver to D3D (Or what ever it is).