Procedure to patch on PBW?

[Dogboy]

I gave a fleet of fighters the order to go to a space yard and become mothballed. They went to the space station and I got a message saying they were successfully mothballed, but they are there at the station, with no symbol indicating they are mothballed. I can give them an order to move, which they seem to accept. And, if I break the fighter groups out of the fleet I can order each group. However, the "mothball" order is grayed out. Am I missing something obvious? Thanks for any help.