But I think the misunderstanding is yours Steve. Metagrid is sending MIDI commands - I can see them in Cubase, and Metagrid have confirmed it to me.
Also, Cubase IC Pro has exactly the same issue and that’s not using key commands either.
I don’t know how your solution works but as you can see I’m not the only one reporting this issue with Metagrid, etc.
So there certainly is a “focus problem”.