Filter has no fields

Jmix 1.3

I have a problem with the filter.
On a specific screen, I have to load data from Google BigQuery to my custom dto and then populate the table. Data is loaded to the table successfully but when I click Add Search Condition, the filter box is empty, there is no field to select. Please advise,
In Controller:

  • LoadDelegate of DL: return Collections.emptyList()
  • onInit:
List<DTO> dto = loadData();
tableDc.setItems(dto)
tableDl.setContainer(tableDc)

In XML:

<data readOnly="True">
<collection id="tableDc" class="...DTO">
<loader id="tableDl"></loader>
</collection>
</data>
...
<filter dataloader="tableDl"><properties includ=".*"/></filter>
<groupTable dataContainer="tableDc"> ....

Above is some code I cut from the project just so you have a better view of the project. Let me know if it helps,
Thanks,