It would be cool if we could flag windowmenu options in some way to get a check mark next to them, to indicate that the selection is active or not. Something like can be seen in the main output right-click menu...
Currently, it can be done through modifying the name of the option, but that kicks the name over to the side, whereas the check mark in the image above occupies its own space.
Try a Windows Explorer window, the View Menu. The display as Tiles/Small items/list/details/etc functions as a radiobutton. It's another kind of menu item. ;)
It seems to have lost favor though, compared to pretty much all other options.
A caveat of the radio button is that you need some way of showing which buttons are in that radio group, and then a way to show which one is selected. And if you want to have multiple radio groups, there needs to be a way to tell MUSHclient which one is which
The selecting would still be a pretty manually scripted effort I think, although I haven't checked on the functionality per se. So yeah, that would be the scripters responsibility.
Groups are usually denoted by either only having a single item in a menu, or by putting the relevant choices inbetween a bunch of separators.