Hmm. Discovering the differences almost always leads to the answer. (I think I got that in a fortune cookie once.)
If one list is using Content Types, then the column in question is a Site Column. That Site Column is a lookup into the same list as in the Calendar, right?
What if you use the same Site Column in both places?
M.
If one list is using Content Types, then the column in question is a Site Column. That Site Column is a lookup into the same list as in the Calendar, right?
What if you use the same Site Column in both places?
M.