Remov type from field list on campaign member as related list

I'd like to remove "Type" from the selected field list in the campaign member related list on campaigns. Trying to do so pops an alert: 

Error: Type can't be removed and must be the first field in the related list. To remove, set another field as the Name field and the first field in the related list.

Could you point me to further information on this? How do I set a field as a name field, and what should I be aware of in doing so?

Thanks in advance!

#Related List #Campaign Members List