Reassignment issues

Whenever I reassign an item that can be damaged or reloaded, eg a wooden needle or improvised lockpicks, the assigned letter is lost whenever it is reloaded or damage via use. It’s annoying! Is there any way to prevent this and keep the assigned letter from being lost?

I think there’s something to do with favouriting if you want to preserve inventory letters, have you tried it?

Ah, thank you. Was not aware of this. Seems to work for the needle but I’ll need to do more testing on the lockpick stack.