When choosing "Rename Branch", the window comes up, but no control has keyboard focus. Given the main purpose is to change the branch's name, the text in the field containing the branch name should really be selected.

Note: The "full keyboard access" setting on macOS is the default ( off )

This should really be taken care of by your GUI framework by default. So I'm assuming whatever you're using is not AppKit, which by default grabs the first text field unless you somehow manage to remove fields without updating the key view loop properly. Might be worth ensuring that the framework takes care of this, as I think other spots in the UI also have this issue.