Today I upgraded my Ubuntu to 20.04 version and noticed that shortcuts commands using Ctrl and Shift buttons are not working. It not depends on selected language, it's just ignores Ctrl. How can I fix that?
Try to review the input sources settings -> Region & Language -> Input sources, maybe you have misconfigured that. On the other way, you can use an application in order to view if the system catches the keystroke. You may want to look at something like https://www.omgubuntu.co.uk/screenkey-show-key-presses-screen-ubuntu