Thank you both for your answers.

@royUK the purpose is to have an intelligent drop down, that picks unique values from the column that holds the validated cell, and shows them in a list. It's not for me its for an asset management firm...

@antoka05 I think that did it... However, I for some reason had allready changed from ; to , and I can't remember why (...) I guess it's wait and see. Thanks!