After upgrading to Ubuntu 20.04 today I found that my monitor configuration is not working properly any more. I have a 4k primary display in landscape and a 1080p secondary display in portrait (right) mode next to it on the right. I have an ATO GTX 950 videocard to power them both.
After upgrading from 19.10 to 20.04 I fond that panel (that I use on top using 'dash to panel' extension was partially on second monitor. Also windows are weirldy displayed partially across both screens in some circumstances. After more investigation I found that when I go to the second screen and move mouse cursor to right there seems to be more desktop there and the whole desktop shifts. Itś almost like the desktop is too wide for the screens.
If I change second monitor to "normal" landscape orientation the panel shifts back fully to my primary monitor (instead of being partially on primary and partially on secondary) and all works normally (except that I cant use portait mode which I want to do and always could do before. When I "move" second monitor to left or above secondary primary monitor in display settings everything also looks and behaves normal (also in portrait) only the my mouse movements become illogical (I have to move cursor left off primary screen to get to monitor on the right.
Anybody have a clue what to do about this (except for possible bugfix in Ubuntu or display driver)?