docs: public void showLoadingAnimation(String msg) {
  
          removeLoadingAnimation();
          m_loadingPanel = new FlowPanel();
          m_loadingPanel.addStyleName(I_CmsLayoutBundle.INSTANCE.uploadButton().loadingPanel());
          m_loadingPanel.addStyleName(org.opencms.gwt.client.ui.css.I_CmsLayoutBundle.INSTANCE.generalCss().cornerAll());
  
          CmsLoadingAnimation animationDiv = new CmsLoadingAnimation();
          animationDiv.addStyleName(I_CmsLayoutBundle.INSTANCE.uploadButton().loadingAnimation());
          m_loadingPanel.add(animationDiv);
  
          HTML messageDiv = new HTML();
          messageDiv.addStyleName(I_CmsLayoutBundle.INSTANCE.uploadButton().loadingText());
          messageDiv.setHTML(msg);
          m_loadingPanel.add(messageDiv);
  
          m_container.add(m_loadingPanel);
      }