Hi,
If you are the "leader" of the group, you can view other members' data, but otherwise you will not be able to see their Projects etc.
This might explain why you can do this sometimes and not others, depending on whether you are logged in as the leader of a group or not?
Sharing and reusing tags is one of the many features that will become possible with proper permissions functionality. However, I'm sure you can appreciate that this is going to be a lot of work to get this right.
Current ticket is
http://trac.openmicroscopy.org.uk/omero/ticket/1434Thanks for your comments...