Bug 130976 [Viewers] Error is calculation of parent path when calling TreePathViewerSorter
There is an error in the parent path calculation in AbstractTreeViewer#getSortedChildren. If the input of the viewer is passed, a tee path of length one is passed to the sorter but a null should be passed (as mentioned in the method spec). I will attach a patch.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
*           the SWT control
     * @param listener
     *           the SWT tree listener
     */
    protected abstract void addTreeListener(Control control,
            TreeListener listener);
    
    protected void associate(Object element, Item item) {
        Object data = item.getData();
        if (data != null && data != element && equals(data, element)) {
            
            
            
            unmapElement(data, item);
            item.setData(element);
            mapElement(element, item);
        } else {
            
            super.associate(element, item);
        }
    }
    /**
     * Collapses all nodes of the viewer's tree, starting with the root. This
     * method is equivalent to <code>collapseToLevel(ALL_LEVELS)</code>.
     */
    public void collapseAll() {
        Object root = getRoot();
        if (root != null) {
            collapseToLevel(root, ALL_LEVELS);
        }