CGridView passing all values from activeListBox

I’m having an issue when including a listbox in the filter area of the cgridview. It displays fine but when I select more than 1 item in the list (multiselect) - only one item gets passed on. The search results show only results for one, and the filter comes back with only one item in the list selcted.

The $_GET also has only 1 item… However when I include the listbox in the "advanced search" area (in _search.php) - it works fine, and the listbox inthe filter area also shows the multiple selections correctly.

The issue SEEMS to be (I’m guessing here) with the javascript sending the Ajax request… can you please help.