Bug 125272 [Viewers] AbstractTreeViewer needs remove(Object parentElement, Object[] childElements)
There is an add(Object parentElement, Object[] childElements) but no corresponding remove(). Without this method, if you have an element that appears under multiple parents, the only way to get model and viewer in sync after removing the element from just one of its parents is calling refresh().
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
super.disassociate(item);
        
        
        
        if (usingElementMap())
            disassociateChildren(item);
    }
    /**
     * Disassociates the children of the given SWT item from their
     * corresponding elements.
     * 
     * @param item
     *           the widget
     */
    private void disassociateChildren(Item item) {
        Item[] items = getChildren(item);
        for (int i = 0; i < items.length; i++) {
            if (items[i].getData() != null)
                disassociate(items[i]);
        }
    }
    
    protected Widget doFindInputItem(Object element) {
        
        Object root = getRoot();
        if (root == null)
            return null;
        if (equals(root, element))
            return getControl();
        return null;