Shift + Alt + Ctrl + A hotkey

I'd like to define a hotkey/shortcut with three modifier keys, such as "Shift + Alt + Ctrl + A". I can't seem to get DO to do this. Is there a reason why or a workaround?

Just push the key and it should work, unless some other software is intercepting it.

Do other similar keys work? e.g. Ctrl + Alt + Ctrl + S?

For me, Ctrl + Alt + A triggers a password manager, which intercepts it and doesn't care if the Shift key is down or not, but other letters work, and A also works if I close the password manager.

You're right, some other software was intercepting it.