So, I'm at Jangala. My options are:
1. Open the comm directory
2. Take a shuttle to visit the Luddic shrine
3. Take a shuttle down to visit a dockside bar
4. Trade goods or hire crew [I], buy or sell ships [F], or refit [R]
5. Repair your ships at the Dockyard
6. Establish a new Settlement
7. Consider your military options
8. Special functions
9. Visit the D-MOD service center
null. Leave [Esc]
Options six through nine are various mod-added things.
Option "null" just doesn't quite look right, though.
I'd suggest allowing an option 0 (zero) for a tenth, then if options go to 11 total making "leave" be "Esc. Leave" instead of "null. Leave [Esc]", and then... well, okay, I'm not quite sure what should come after that if mods keep adding more things, but I don't think it should be "null".
Posted in suggestions because this isn't exactly a bug per se: the UI still works.