I have been using Kali Linux for quite some time now and i like it so far. but recently i had the problem that i could not fix. Kali, for some reason, just got rid off all the maximize, minimize and close buttons on top of every app that i have. you know three buttons on the top right hand corner? they are all gone. i was able to fix that last time by reinstalling the whole OS. i dont want to do that again. This is an example of how my file explorer (Thunar) looks like right now without the top right hand corner buttons gone:
example screen

here is my OS details if that will help:
OS details

Reinstalling Kali worked once. but i dont want to do it again.