code: @Override
      public void setDataToggle(final Toggle toggle) {
          toggleMixin.setDataToggle(toggle);
  
          // We defer to make sure the elements are available to manipulate their position
          Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
              @Override
              public void execute() {
                  separator.removeFromParent();
                  caret.removeFromParent();
  
                  if (toggle == Toggle.DROPDOWN) {
                      addStyleName(Styles.DROPDOWN_TOGGLE);
  
                      add(separator, (Element) getElement());
                      add(caret, (Element) getElement());
                  }
              }
          });
      }
docs: Specifies that this button acts as a toggle, for instance for a parent {@link org.gwtbootstrap3.client.ui.DropDown}
  or {@link org.gwtbootstrap3.client.ui.ButtonGroup}
  <p/>
  Adds a {@link Caret} as a child widget.
  
  @param toggle Kind of toggle