Bug 93360 [Viewers] getChild still used in indexForElement
indexForElement() in AbstractTreeViewer still uses getChild() and not getChildren(). This should probably also change to using getChildren() and do the same thing as insertionPosition().
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
*/
    public void collapseToLevel(Object element, int level) {
        Assert.isNotNull(element);
        Widget w = findItem(element);
        if (w != null)
            internalCollapseToLevel(w, level);
    }
    /**
     * Creates all children for the given widget.
     * <p>
     * The default implementation of this framework method assumes that <code>widget.getData()</code>
     * returns the element corresponding to the node. Note: the node is not
     * visually expanded! You may have to call <code>parent.setExpanded(true)</code>.
     * </p>
     * 
     * @param widget
     *           the widget
     */
    protected void createChildren(final Widget widget) {
        final Item[] tis = getChildren(widget);
        if (tis != null && tis.length > 0) {
            Object data = tis[0].getData();
            if (data != null)
                return; 
        }
        BusyIndicator.showWhile(widget.getDisplay(), new Runnable() {
            public void run() {
                
                
                if (tis != null) {