Display a ComboBox automatically

Help & Support
1

I was trying to display a ComboBox automatically in the following way, but Opus doesn't seem to accept it, does anyone know of any alternative?

if (coincidencias > 0) {
    dlg.Control('genero').dropdown = true;
}
2

Control

There is not any "dropdown" property available. Where did you find that?

3

I found that instruction on a JavaScript site.