Clear active spells from actor when he disappears from scene
According to my testing, Morrowind cleans up active effects from actor in these cases:
- When his cell is unloaded
- When he is disabled via script
- When he is teleported to an inactive cell
Note that effects are cleaned up for player's followers, which are moved to new cell with player.
I suppose that Morrowind does it to do not update magic effects for actors in inactive cells.
This feature may be a quite hard ro implement in OpenMW since our current approach to move actor to another cell is to "remove old actor instance from scene and spawn a new one".