With the new update from darkorbit hangar the following options doesnt work:
• repair from hangar 5-3
• repair from hangar 5-2 base
You can use the option to repair on spot. As this is new feature from darkorbit it will take time until update, please be patient.
As I see the feature is not completed or really improved badly.
EDIT: as you add ships to favorite, they reappear in warp menu and in hangar main menu
The problem is they dont have a number in warp menu, we will see if bigpoint do something about this or we make some changes.
To work sell function make sure you add your ship as favorite and change in bot according to number given in hangar main page.