Thanks Island Dog. Well, it kinda worked. Basically, when I checked the "View" in the Fences, the Locked option was unchecked. So, in theory, icons should be able to be dragged into a fence. On a hunch, I locked the fences, then unlocked them and now it works. A bit bizarre, but it did fix my problem. However, shouldn't work that way - a bit of a quirk.
Thanks again...