code: public HandlerRegistration addIconClickHandler(final ClickHandler handler) {
  
          final HandlerRegistration internalHandlerRegistration = m_iconPanel.addDomHandler(
              handler,
              ClickEvent.getType());
          m_iconClickHandlers.add(handler);
          HandlerRegistration result = new HandlerRegistration() {
  
              public void removeHandler() {
  
                  internalHandlerRegistration.removeHandler();
                  m_iconClickHandlers.remove(handler);
              }
          };
          return result;
      }
docs: Adds a mouse click handler to the icon panel.<p>
  
  @param handler the click handler
  
  @return the handler registration