Pick Borderless Window. Then it will work like you want.

i am glad alt-tab is not allowed since you need to use alt a lot!
but you can go to fullscreen mode and if you want to go to windoes just ctrl+alt+delete and then task manager.
make sure you had your game paused thought with esc and stay on a menu or you may die in the background while you are working on windows.

Ah. I might have missunderstood something. I can't get on the desktop either like i explained above. But the game is not overlaying anything else so you can get browser or something else above the game.

I see...but its strange because my friends can alt + tab to desktop but i cant..and i heard other as well cant

No matter what screen mode i select, then i cant alt + tab or use windows keys to select anything on the desktop..so when i play Wolcen then i need to exit the game or hook up another monitor...fail..