code: public boolean removeDivider(String text) {
          for (int k = 0; k < list.getWidgetCount(); k++) {
              Widget w = list.getWidget(k);
              if (isDivider(w) && w.getElement().getInnerText().equals(text)) {
                  list.remove(k);
                  items.remove(k);
                  return true;
              }
          }
          return false;
      }
docs: Remove the divider with the given text. This method will search all the dividers and remove the first divider
  found with the given text.
  
  @return true if a divider with the given text was found and removed, otherwise false.