I was trying to replace an old qt version that was installed in my ubuntu installation with no success. Now I've simply given up. In the process I had added the Bionic sources to my apt sources list file and it deleted/added a lot of things.
When I started my gnome desktop it took some time more than usual and showed the desktop. But as you can see in the pictures below, gnome apps like the terminal, file manager etc. are not being displayed properly and instead I can just see a black window. Even the system tray at the bottom is messed up with artifacts.
I've now removed the Bionic sources and reinstalled ubuntu-gnome-desktop yet nothing has changed. Can someone tell me what's going on and how do I fix it?