Bug 141192 [Viewers] Javadoc change about multiple equal elements in StructuredViewer and AbstractTreeViewer
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* <code>null</code>.
	 * 
	 * @param elementOrTreePath
	 * @return the parent element, or parent path, or <code>null</code>
	 * 
	 * @since 3.2
	 */ 
    protected Object getParentElement(Object elementOrTreePath) {
    	if(elementOrTreePath instanceof TreePath) {
    		TreePath treePath = (TreePath)elementOrTreePath;
    		if(treePath.getSegmentCount() <= 1) {
    			return null;
    		}
			return (treePath).getParentPath();
    	}
        IContentProvider cp = getContentProvider();
        if (cp instanceof ITreePathContentProvider) {
			ITreePathContentProvider tpcp = (ITreePathContentProvider) cp;
			TreePath[] paths = tpcp.getParents(elementOrTreePath);
			if (paths.length > 0) {
				if (paths[0].getSegmentCount() == 0) {
					return getInput();
				}
				return paths[0].getLastSegment();
			}
		}
        if (cp instanceof ITreeContentProvider) {
        	ITreeContentProvider tcp = (ITreeContentProvider) cp;
        	return tcp.getParent(elementOrTreePath);
        }