code: public void insert(E tabContent, String tabName, int beforeIndex) {
  
          m_tabPanel.insert(tabContent, tabName, beforeIndex);
          m_tabPanel.checkTabOverflow();
      }
docs: Inserts a widget into the panel. If the Widget is already attached, it will be moved to the requested index.<p>
  
  Wrapper function for {@link com.google.gwt.user.client.ui.TabLayoutPanel#insert(Widget, String, int)}
  
  @param tabContent the widget to be added
  @param tabName the text to be shown on its tab
  @param beforeIndex  the index before which it will be inserted