Edit Fixtures Gobo Slots

If I edit the default gobo slots of a fixture is it possible to use any of the available alternatives or can I only use some of the certain options?
I was trying to edit some gobo slots today and after editing several gobos on both the static and fixed wheel several of the auto-pallets were greyed out and became unresponsive?
So basically editing the gobo name made the pallet un-useable?
Mac 700 Spot fixtures in basic mode.

Regards C