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
ArrayList result = new ArrayList(items.size());
        for(Iterator it = items.iterator(); it.hasNext();) {
        	Item item = (Item) it.next();
        	Object data = item.getData();
        	if (data != null) {
        		result.add(data);
        	}
        }
        return result.toArray();
    }
    /**
     * Returns whether the node corresponding to the given element or tree path is expanded
     * or collapsed.
     * 
     * @param elementOrTreePath
     *           the element
     * @return <code>true</code> if the node is expanded, and <code>false</code>
     *         if collapsed
     */
    public boolean getExpandedState(Object elementOrTreePath) {
        Assert.isNotNull(elementOrTreePath);
        Widget item = internalGetWidgetToSelect(elementOrTreePath);
        if (item instanceof Item) {
			return getExpanded((Item) item);
		}
        return false;
    }
    /**
     * Returns the number of child items of the given SWT control.
     *