I found this question on the US forum, but since Blizzard has decided I’m not allowed to post there, being a EU-player, I figured I’ll post the solution here. This is cut and paste from a Google search.
Why is Ctrl+Shift+0 not working?
Settings > devices > typing > advanced keyboard settings > input language hot keys > advanced key settings > change key sequence, then set both “switch input language” and “switch keyboard layout” to “not assigned” to enable ctrl+shift+0.
Not only Ctrl+Shift+0 but also just Shift+0 must not be working.
This seems to be an issue because the combination Shift+Insert is one of the 2 mostly used to switch keyboard layouts in Windows (the other being Alt+Shift). When you have NumLock disabled, Numpad 0 acts as if you press Insert, so when you press Ctrl+Shift+Numpad 0, Windows acts as if you pressed Ctrl+Shift+Insert, and there it catches Shift+Insert and doesn’t transmit it to the game. The exact same reason is why you can’t bind Alt+F4 to anything.
Ctrl+Shift alone changes keyboard layout within the language, and so does Alt+Shift between he languages - if I recall correctly. And the 0 is for changing to a particular one, isn’t it?
Of course, so does Win+Space (go through the list) and Win+Shift+Space (previously used one), so none of this is needed. Not sure why it’s still there.
But Windows re-enables them occasionally after turning them off, providing a little “helpful” message in the lower right corner that hey, by the way, you can use these keybinds! And then I have to go in there and turn it off. Again.
This is super painful at work because I use ctrl+shift all the time to write all of APL’s various symbols, such as these silly bois: ⍨⌶⍫⍒⍋⌽⍉⊖⍟⍱⍬⌹⍠⍤⌸⌷⍎⍕⍞⍣⍙⊣¢⍝ We just got some Chinese employees and they need the IME to write to each other and they are losing their minds over this.
I also had to deal with that problem there because I used to play left-handedly. My left hand was on my mouse and I moved with PLÆØ
Thank God WoW works on Linux and macOS…