Sales cloud and Marketing cloud are integrated using MCC. Entities have been setup under Data Sources and sendable Data Extensions are populated. In addition, the Salesforce entities are in an attribute set associated.
When attempting to create a filter definition in Email Studio or a SQL activity in automation studio, the Salesforce Data Extensions are not available through the UX to drag and drop. In the SQL activity, I can write SQL that accesses the tables though.
I need to have these DEs available for drag and drop so business users can create data filters to populate sendable DEs to be used in journeys. What am I missing? Why are the synchronized DEs not available to drag and drop in either filter definitions or SQL activities? What is different about these vs sendable DEs I create myself which seem to have no problem showing up in the drag and drop interface.