virtual copies not showing up in collection

I have run across a problem recently, that I know did not used to be a problem. I am using Lightroom 4.3. I have been working in a collection that is part of a collection set. When I right click an image and select "create virtual copy", it does not show up in the collection. If I go to the folder where the actual image resides, the virtual copy is there. To get it to the collection, I have to drag and drop.
I have no filters selected (yes, I mean that I don't have "show only master copies" selected).

Anybody have a clue as to what the problem is?

Thanks,
Steve Wheatcraft