I have a DVWP that I want to filter using a dropdownlist. The DDL is
populated from a list of categories, and the filter is based on a Control
parameter that maps to the DDL. The filter field on the DVWP is called
Categories; it's a multiple-choice lookup field that pulls its data from the
Categories list. The filter states that if the Categories field contains
the DDL value parameter, then display that record.

All is well when the DDL's blank item is selected. However, no matter what
value I choose, the DVWP returns no results. I've added the values of the
parameter and the Category field to the page so I can see them; from my view
of the HTML source in the browser, the values match exactly, even down to
casing (as they should). I tried adding a translate function on both side
to make everything case-insensitive, and still the filter brings back
nothing.

Has anyone seen this happen before? Any suggestions? I'm pulling my hair
out here, and I can ill afford the loss.