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
disassociate(items[i]);
        }
    }
    
    protected Widget doFindInputItem(Object element) {
        
        Object root = getRoot();
        if (root == null)
            return null;
        if (equals(root, element))
            return getControl();
        return null;
    }
    
    protected Widget doFindItem(Object element) {
        
        Object root = getRoot();
        if (root == null)
            return null;
        Item[] items = getChildren(getControl());
        if (items != null) {
            for (int i = 0; i < items.length; i++) {
                Widget o = internalFindItem(items[i], element);
                if (o != null)
                    return o;
            }
        }
        return null;
    }
    /**