After upgrading to Lubuntu 16.04 from 15.10 I found a strange problem - Steam login window will appear, but when I try to click on it or manipulate with some other window, it gets simply "overwritten" with surrounding graphics, like parts of another window etc. And the "click" has no other effect.
It's really strange and I've never encountered similar error before. The even stranger part is, that this problem occurs only with Steam and nothing else.
I have tried to completely reinstall
steamcmd packages and even manually remove
/home/.steam/ folder, but nothing worked.
Do you know, how can I repair it?