Filtering Vendor list for a project

Hello,

I am trying to filter vendor list for RFB business process. I have created a Shortlist BP with type Line items to filter company Business Process records. I have used the Vendors BP with the following settings:

I have added Vendor field in the Reference Process(also detail form) and tied it to Vendors BP. I deployed Shortlist BP successfully and created a record in the project with a few vendors at status Open. When I use Initate Bid and click Add button on RFB I am still getting the full list of vendors. There is not much info about this BP type in documents. It says: