Invalid hotkey bug

Issue Description: When trying to set the hotkey to Shift+Z Overwolf says invalid hotkey, but Shift+Tab or Shift+Space is accepted. Is this a bug or is it a feature?

Can you reproduce it (exact steps to reproduce): go to settings and try to set any of the hotkeys above

Impact for my app: not so much
Do you currently have a workaround?: no

Shift + alphanumeric hotkeys are not allowed.