Keyboard Shortcuts

[Simon Colston]

Fedora Workstation 31 GNOME

My installation has a default of English (UK) but occasionally I use Japanese so I installed Japanese language support. 
When using the Japanese IME one of the keyboard shortcuts is Alt+`.  However, when I use this it brings up an 
application switch screen.

I looked through the Settings -> Devices -> Keyboard Shortcuts but there is nothing defined for Alt+`.  I also noticed 
that "Switch Application" is set to Super+Tab (which works) but Alt+Tab does the same thing even though this is not 
defined anywhere.

So my question is, how can I disable these unwanted keyboard shortcuts?