I have always assumed that Shift-Ctrl is interchangeable with Ctrl-Shift as modifier to certain keystroke commands. For no particular reason, I have been in the habit of typing Shift-Ctrl. Since upgrading to 22-04, Suddenly I find that only Ctrl-Shift is working. While I may have to retrain my fingers, I wonder why this has occurred, and whether there is a simple way of changing back.
Ubuntu 22-04
I have discovered that this arises when I set the pointer location flag in Tweaks. The pointer location shortcut key is Control. Presumably the system 'steals' the Ctrl when it is typed following the Shift. It seems surprising that it happens that way round (Shift-Ctrl) not the other (Ctrl-Shift), but it is what it is.