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
}
                
                if (needDummy && !haveDummy) 
                    newItem(ti, SWT.NULL, -1);
                return;
            }
        }
        if (childElements.length > 0) {
            Object[] filtered = filter(childElements);
			if(getSorter() != null)
				getSorter().sort(this,filtered);
            createAddedElements(widget, filtered);
        }
	}
	/**
     * Create the new elements in the parent widget. If the
     * child already exists do nothing.
     * @param widget
     * @param elements Sorted list of elements to add.
     */
    private void createAddedElements(Widget widget, Object[] elements) {
		if(elements.length == 1){
			if (equals(elements[0], widget.getData()))
				return;
		}
		
		ViewerSorter sorter = getSorter ();
		Item[] items = null;
        if (sorter == null) {
		   items = getChildren(widget);