Select Duplicates is dimmed

The Select Duplicates menu item is dimmed and I’ve no idea why. I thought it might be because I had not sorted the field, but sorting the field did not help. Dimmed menu items are most always frustrating.

Is this still on the list for implementation?

In spite of the reminder in BitBucket, I forgot all about this. It turned out to be a much more significant project than I thought it would be, but it is done now and will be included in the next release.