I recently installed Linux Mint Cinnamon on a laptop, and I’m having a two-sided issue. Web searches have yielded no solution. I’m also very new to Linux.

Problem 1: When alt-tabbing out of a fullscreen application (at this moment, Helldivers 2), the application will minimize, but I cannot restore it. It will appear for roughly half a second, and then re-minimize. I can hear the game still running in the background.

I have tried alt-tab, super+number, and right-click>restore. None seem to work.
I have tried disabling thumbnails for windows, no fix.
Disabling effects, no fix.

Problem 2: As a workaround for problem 1, I tried borderless fullscreen. It works, but there is a white, 1 px border around the screen. I have tried changing themes, no fix. Same thing with disabling effects. I do like the Mint-Y theme, but there’s no longer an option to change window borders, from what I’ve researched. Again, trying a different theme didn’t seem to get rid of the white border.

Please help.