How to make IDEA handle JavaFX sub-controllers issues correctly?

<VBox fx:controller="com.foo.MainController"> 
...
    <fx:include fx:id="dialog" source="dialog.fxml"/>
...
</VBox>

public class MainController extends Controller { 
    @FXML private Window dialog;
    @FXML private DialogController dialogController;

    ...
}

The above code shows the nested controller mapping.

But IDEA just regard the dialog in [fx:id="dialog"] as unresolved reference.

How to make IDEA correctly detect the sub-controller usage?