"Edit multiple workitems" Some Field missing

i try to edit multiple work items through the workitem query editor.

The field I want to change is "Tag".

Further I want to set a link of multiple workitems to a specific workitem.

When I go to the Workitem Query Editor and select "Edit multiple workitems" I see a dialog "Add Attribute Change". But there is no Tag Field listed and I also dont see a item to set the new link.

Did someone know how to do this?

Thanks in advance.

Alex