[Evolution] Categories in Evo/EWS

[Joakim Tjernlund <Joakim Tjernlund transmode se>]

There is a Show Filter in every Contact list where one can filter  on
different categories.
However, no contact, my own list or Def Global Adress List has a category
assigned, nor can I assign a category in any list as the Category Field is greyed out.

How can edit this field and how to see what categories Def Global Address List has(read from EWS)?

Can I also ask what the difference between GAL and Def Global Address is ? My GAL is empty