Windows MKVToolnix GUI 83.0 Multiplexer: Keyboard shortcuts to modify tracks are disabled until "Multiplexer" menu is expanded

When opening files via drag&drop to the multiplexer, the keyboard shortcuts for languages, setting default or forced track, and others don't work until the "Multiplexer" menu is clicked upon (with no action required).

I suspect that the issue could be related to #3573 (closed), in fact I thought it would be fixed as the issue was closed, but saw that it referred to the "Header Editor" and not the "Multiplexer", so I suspect it could be the same issue popping its head in another place (I remember the feature working properly in version 75 or 76).

Thank you very much, hope the info and report was useful enough.