/**
  * @param parentManager
  * @param itemModel
  * @param ci
  */
 private void addToManager(
     ToolBarManager parentManager, MToolBarElement model, IContributionItem ci) {
   MElementContainer<MUIElement> parent = model.getParent();
   // technically this shouldn't happen
   if (parent == null) {
     parentManager.add(ci);
   } else {
     int index = parent.getChildren().indexOf(model);
     // shouldn't be -1, but better safe than sorry
     if (index > parentManager.getSize() || index == -1) {
       parentManager.add(ci);
     } else {
       parentManager.insert(index, ci);
     }
   }
 }