pgadmin3: can't locate server: what am I doing wrong?

I am a longtime user of postgersql, using it as a backend and using odbc to connect and it has been an amazingly stable and useful database manager.

Now, a longtime Windows user (disgruntled) I am trying to set up a development platform on a local Suse Linux box which includes a local install of postgresql.
Last week I successfully installed postgersql and created a database, but today pgadmin3 doesn't seem to find it!
Using the unix ps command I see there are postgre processes running, so the server is up.

Logged in as user postgre and invoking pgadmin3, 'Server Groups' is empty.
logged in as user root and 'server groups' is empty.
logged in as fredrated and the server is there.

Can someone explain what this means? Why is the server only visible to this user?

Thanks, Fred