Update the Window onChange?

Hey guys,

how can I update my window with the onChange event? My solution works, but I need the groups to collapse when not visible.

w.DD.onChange = function() { 
     switch (this.selection.text){ 
          case 'Headline': 
               if(w.visiblegroup) 
               w.visiblegroup.visible = false; 
               w.visiblegroup = w.texted; 
               w.texted.visible = true; 
          break; 
     } 
}

I have tried to use w.show, w.update(with documentation, still not sure what .update actually does) after adding the elements in the case itself. But I can't figure this out.

w.DD.onChange = function() { 
     switch (this.selection.text){ 
          case 'Headline': 
               w.add('checkbox', undefined, 'User-Color'); 
               //w.show(); 
               w.update(); 
          break; 
     } 
}

Does anyone have a clue how this might work?

Thanks in advance!