The reason I'm suggesting this is so you know exactly what data is being returned to the form. By adding the data fields onto the form and previewing, you can see the values - but the checkbox control could be hiding something... like blank values.
I'm just not too sharp today. I got it now!
Ok, so the data is showing true or false. The Contracts in the screenshot are both showing up in the drop-down when the corresponding vendor is selected. I changed the filter to Not Equal True but no luck. Sorry to be such ignorant on this one.
Well, I mean - the filter you are using works on the Vendor drop down, right? So I can't really think of any reason why it doesn't work on the contracts dropdown. It really doesn't make sense.
I'll try one more time or I might just give up. Yes, the filter on the Vendor is working fine. So this is what is in my filters. So the AC25_0016 contract shouldn't show up since it's deactivated and expired. Ughh.