OS X Address Book: How do you show all groups for a Contact?

Once upon a time, an early version of OS X Address Book allowed one to see all the Groups to which an address belonged:

InformIT: Mac OS X Unleashed - Address Book: "the group setup window should appear,"

I don't believe there's a group setup window any more. It's easy to add an address to a group, but I don't think there's away to inspect or interact with an address and find out which groups it belongs to.

I often want to do this, particularly when I deal with duplicate address book entries.

Sigh.

I doubt Apple will fix this. If they ever do crack the hood on Address Book, maybe they could also fix the "Find Duplicates" function - such as provide a "show duplicates" option. Or at least document what the merge behavior really is!

Update 2/26/2010: Per Comment by Kate: "Simple. Select the address card you want to find groups for. Press the option key. The groups the address belongs to will be highlighted." Knowing the answer I searched on this, and found only one reference in an old version of Pogue's "Mac OX X" Missing manual series. How did Kate know this?

Update 2/27/2010: It's in the "manual" (online help). Of course. It's not even hard to find. I searched on "show groups" and found:

Select a contact in the Name column.

Hold down the Option key.

Address Book highlights the groups the contact belongs to in the Groups column. If you have a lot of groups, scroll the list to see all of the highlighted groups.

Total humiliation, total fail.