Posted
It appears that on my machine (on Win 10), keyboard shortcuts that involve more than one modifier key do not work at all if the Ctrl key is involved, only shortcuts with a single modifier key work then. I noted that also in the keyboard shortcut editor dialogue, I could only map shortcuts with a single modifier key, other inputs are simply ignored, it seems.
For example, I could map some functionality to the shortcut Ctrl+A (arbitrary example) or Alt+A, but not Ctrl+Alt+A or Ctrl+Shift+A, but Alt+Shift+A works again.