Module Builder Combobox custom modules not loading

Hi All,
i’ve started using (studyng) dolibarr recently and i’ve a problem i dont’find documented eslewhere.

Using ModuleBuilder i’ve created 2 simple modules with all the fields proposed automatically.
In the second module i want to show a combobox with the values of the first one.

According to the istruction i’ve added a filed using this sintax for the type:

When creating or updating a record the combobox shows without errors, but is empty.
I tried to insert directly into the table a value for the field and in view or list show correctly the expected value from the first module…but in edit/add the combobox is still empty.

Is there something i’m missing? I can’t find nothing :frowning:
Thanks all for help!