I'm fairly new to Morrowind modding and when I'm trying to add a spell to a NPC's list of trainable spells it doesn't work. From my understanding to add a spell you:

1. Edit the NPC, click on the Spell list
2. Click on the the Spellmaking tab in Object Window
3. Left click and drag the spell you want into the NPC's spell list tab

This is correct yes? But when I drop the spell into the list nothing happens..

Any ideas? I'm using the TESCS Fix for Steam GOTY Users

Thanks.

edit: Yes I checked the Spells box under Services under AI data and I don't get an error message while in the CS

Uncheck "Auto Calculate Stats" checkbox in NPC's main panel.

That was indeed it, thanks! It was driving me nuts.