How to populate Query Builder data sources?

Hello.  I'm trying to set up a Query Builder component for the first time.  However, all that appears is a dropdown box for Data Source with a single entry, “No options”.  How do I populate it with my map layers?  In the Map component, I have several layer extensions where Query is enabled.  Why wouldn't they show up as Data Sources in the Query Builder?  Is there anything else that needs to be configured?

Thanks,

Chris