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
if (fullMap) {
                associate(element, item);
            } else {
            	Object data = item.getData();
            	if (data != null) {
            		unmapElement(data, item);
            	}
                item.setData(element);
                mapElement(element, item);
            }
            
            SafeRunnable.run(new UpdateItemSafeRunnable(item, element));
        }
    }
    /**
     * Expands all nodes of the viewer's tree, starting with the root. This
     * method is equivalent to <code>expandToLevel(ALL_LEVELS)</code>.
     */
    public void expandAll() {
        expandToLevel(ALL_LEVELS);
    }
    /**
     * Expands the root of the viewer's tree to the given level.
     * 
     * @param level
     *           non-negative level, or <code>ALL_LEVELS</code> to expand all
     *           levels of the tree
     */
    public void expandToLevel(int level) {