docs: public void setControls(FormItem... items) {
          FormItem[] controls = new FormItem[items.length + 3];
  
          int i = 0;
          for (FormItem item : items) {
              controls[i++] = item;
          }
          
          controls[i++] = new SpacerItem();
          controls[i++] = confirmButton;
          controls[i++] = cancelButton;
          
          form.setItems(controls);
      }