We are defining a custom search form for a template that includes three optional fields: quick search (text), date range, and an optional dropdown list of committees. We want users to have the option to *not* select a committee (ie select all or ignore this field if it's empty). We've tried manually adding an empty list item via "define list" in the designer, as well as by adding an empty list item in the customSearchForm.xml, but when selected the query returns no records.
How can we use a dropdown list as an optional element, where we have either an empty list item or an "all selected" list item? We've tried:
<option>[any committee]</option>
<option selected>[any committee]</option>
<option value="">[any committee]</option>
<option value="NOT NULL">[any committee]</option>
<option value="*">[any committee]</option>