multiselect search box

I would like to make one of my search field a multiselect dropdown. i’ve looked around for a post but didnt find one. Is it possible?

See the topic Field Setup → Edit Tag in the help file. You may use CHECKBOX or SELECT with “Multiple” enabled.

Great! I now have a dropdown that has a checkbox for each item I want to search for.

If I only choose 1 it works and I see this search string format
Summarylist.php?x_Expr2=10440&z_Expr2=%3D&cmd=search

This is good because the checkbox is for ID 40110

BUT

when I select more that 1 it returns all records and ignores the search items selected even the the search box shows me what I chose separated by commas.

Am I missing something?