I trying to make an powerapp for teams app.
I have two tables in dataverse:
TableA, principal table with a fieldID and
TableB, child/secondary table with nameofThingFieldID and lookupField2TableA.
There is a relationship one to many on tableA with TableB as the many side and
a many to one relation on tableB ( I know it is just the same relationship from two points of view, but anyway it is there)
I edit TableB and I put some values in some records of the TableB lookup column. It saves fine.
I create the app and generate the first screen automatically from the TableB. No issue here. Everything works. I can edit, save and so on.
To this point everything is as it shoud be.
No I generate the TableA screen. The forms shows only a DataCard for FieldID. No problem: I go to the form properties tab, click on fields and add another Datacard, that with the many2one relationship field:

It is Spanish, but it looks ok: there is a new Datacard with the right field selected and a control type of "see multiple selection of option collection" or something like that.
In fact the DataCard has a Dropdown, with and error: the Items property shows "Choices(-)" instead of a column. In play mode the control shows nothing.
I have tried with "Choices(thisItem.lookupField2TableA)". The error red sign disappears but the control stays blank.
Can somebody out there help, please?