[thelittleone]

I tried these with MacOS Mojave and with Firefox having multiple windows open (not minimized).

Cmd + < opened up a new preferences tab on FF. Cmd + > did nothing.

[thomaslkjeldsen]

Ah, the shortcut for this is keyboard layout specific: https://apple.stackexchange.com/questions/193937/shortcut-fo...

[k__]

I took out a tab of FF into a new windwo and it worked for me.