/** @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object) */
 @SuppressWarnings("unchecked")
 public Object getParent(final Object element) {
   if (element instanceof IFile) {
     return null;
   } else if (element instanceof SimpleTree) {
     final SimpleTree<Object> treeData = (SimpleTree<Object>) element;
     return treeData.getParent();
   } else {
     return null;
   }
 }