Pivot Table Filter Frustration

I've used pivot tables sporadically over the years and never come across this problem until recently. I'm simply trying to limit the data that the pivot table shows and can usually achieve this by selecting the desired records for one of the fields in the field's dropdown box. Suddenly I can neither check an unchecked boxnor uncheck a checked box. Why is it locked????

VBA Noob, unfortunatley this did not reslove the problem. It is still like the filter list is locked down. Actually, now all of the items are checked, like not filtered at all, and I cannot filter it at all.