code: public int getTabIndex(final WComponent content) {
  		List<WTab> tabs = getTabs();
  		final int count = tabs.size();
  
  		for (int i = 0; i < count; i++) {
  			WTab tab = tabs.get(i);
  
  			if (content == tab.getContent()) {
  				return i;
  			}
  		}
  
  		return -1;
  	}
docs: Retrieves the tab index for the given tab content.
  
  @param content the tab content
  @return the tab index, or -1 if the content is not in a tab in this tab set.