Bug 141192 [Viewers] Javadoc change about multiple equal elements in StructuredViewer and AbstractTreeViewer
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* @since 3.1
     */
    protected void internalAdd(Widget widget, Object parentElementOrTreePath, Object[] childElements) {
    	Object parent;
    	TreePath path;
    	if (parentElementOrTreePath instanceof TreePath) {
			path = (TreePath) parentElementOrTreePath;
			parent = path.getLastSegment();
		} else {
			parent = parentElementOrTreePath;
			path = null;
		}
    	
		
        
        if (widget instanceof Item) {
            Item ti = (Item) widget;
            if (!getExpanded(ti)) {
                boolean needDummy = isExpandable(ti, path, parent);
                boolean haveDummy = false;
                
                Item[] items = getItems(ti);
                for (int i = 0; i < items.length; i++) {
                    if (items[i].getData() != null) {
                        disassociate(items[i]);
                        items[i].dispose();
                    } else {
                        if (needDummy && !haveDummy) {
                            haveDummy = true;
                        } else {