Issue with running flrig1.3.49 under lubuntu 19.10 Mate

I am using Lubuntu 19.10 Mate on my two laptops (Thinkpad X230 & HP 6910p) and have installed flrig-1.3.49 on the X230 to use it with my amateur radio (Elecraft KX2). So far all seems to be working BUT I cannot check any tick boxes in flrig. I have installed flrig also on my HP Laptop and also on my desktop pc (Ubuntu 19.10. Gnome) based on the same install guide for both. Same happens on the HP but NOT under Gnome. I also have started flrig in a terminal, but there's no errormessage and no hint at all that something is not working.
In addition I have confirmation from the flrig forum, that it seems to be an issue with Mate and NOT with flrig itself.

Would anyone have an idea to localize the issue exactly or even get it resolved with the setup I am running (=> NO installation of Gnome :wink: )?

Thanks and kind regards from Germany

Hi all, is there really noone having an idea, what I could do / where I could check to at least narrow the reasons for the issue?