Insane lagginess on Linux on tabbing out fullscreen

[RudiAusBuddeln]

This mod is beautiful. Unfortunately, if I have it installed (not necessarily actively blurring something) and I am in F11 fullscreen and I tab out, the computer becomes royally fucked up and almost unusable due to the slowness. The first time this happened I could barely open a tty to kill java.

I am absolutely sure it is Blur. I have tested it with only this single mod installed. There is no information in the console. Given that it only occurrs in fullscreen, could it be a bug in Minecraft? Do you have any idea what might cause this?

[TheKodeToad]

On Minecraft 1.8 fullscreen has some pretty big issues. In versions after 1.12 fullscreen works fine.

[TheKodeToad]

Maybe you could try using Fullscreen Windowed?