Bug 171649 [Viewers] AbstractTreeViewerisExpandable(elementOrTreePath) is not called when using a ITreePathContentProvider
Build ID: 3.3M3 More information: see AbstractTreeViewer.java, line 1974, the content provider hasChildren() should not be called directly
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
*            the parent path if it is knwon or <code>null</code> if it
	 *            needs to be determines
	 * @param element
	 *            the element
	 * @return whether the given element is expandable
	 */
	private boolean isExpandable(Item item, TreePath parentPath, Object element) {
		if (isTreePathContentProvider()) {
			TreePath path;
			if (parentPath != null) {
				path = parentPath.createChildPath(element);
			} else {
				path = getTreePathFromItem(item);
			}
			ITreePathContentProvider cp = (ITreePathContentProvider) getContentProvider();
			return cp != null && cp.hasChildren(path);
		}
		return isExpandable(element);
	}
	
	protected void labelProviderChanged() {
		
		Control tree = getControl();
		tree.setRedraw(false);
		
		internalRefresh(tree, getRoot(), false, true);
		tree.setRedraw(true);
	}
	/**
	 * Creates a new item.