Bug 89606 [Viewers] Remove protected API added to support prototype of grouping by working sets
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
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 {
							items[i].dispose();
						}
					}
				}