I didn't test with Calculator, but for me when I run Calculator it is focused with or without the patch. I don't seem to have a problem with that one. And I'll also note that the loss of focus only happens when another window is already open.
The two apps I really see a problem with are Terminal and AppCenter. The other apps I've tried now don't seem to have the focus problem. You might try testing with those two.
I didn't test with Calculator, but for me when I run Calculator it is focused with or without the patch. I don't seem to have a problem with that one. And I'll also note that the loss of focus only happens when another window is already open.
The two apps I really see a problem with are Terminal and AppCenter. The other apps I've tried now don't seem to have the focus problem. You might try testing with those two.