I have set up two web parts - one is a list (source) and the other is a grouped (collapsed by default) view of a library, which includes a column with the same possible values as the source list.  I have set up a web connection so that when the selects a value from the list, it will filter the library, showing only the documents that are associated with that value.  It appears functional at first - clicking on a value decreases the number of documents "displayed" in the library, as indicated by the number in parentheses for each group.  Here's the bug:  when the user clicks on the "+" to expand a group and view the documents, ALL the documents are there (not just the filtered ones), even though the number in parentheses for the group still reflects the (smaller) filtered number.

Furthermore, If I edit the view to default to "expanded," the web part and its connections work fine, correctly filtering and displaying only the relevant documents.  It appears that the problem only occurs when the groupings are collapsed initially.  When a user clicks to expand the category, it loses the filter (but not the number of filtered items), displaying all items.  Ideas?