I currently have gufw 0.20.1_beta2 installed (which I did the testing on in my previous comment). When I previously had gufw 0.20.0-0ubuntu2 installed, I also got the crash via the menu.
I currently have gufw 0.20.1_beta2 installed (which I did the testing on in my previous comment). When I previously had gufw 0.20.0-0ubuntu2 installed, I also got the crash via the menu.