Ranorex, unable to bound variables and data source

I'm trying to use data driven testing with Ranorex (Ranorex user guide)

I have a simple data connector

The variables I've created from the recording module are automatically available from the "Bind parameters to variables section".

However I can't bind the data source to variables...

How to create these variables ?

Thanks for your help !

Note that I'm using Ranorex 9.3.4

OK, data binding is working if I define the data source on a "Smart Folder" object (2).

Note that I still don't know why it does not work with "Test case" object (1)