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(lastInsertion == items.length)
					index = -1;
				else{
					while(lastInsertion < items.length && sorter.compare(this,element,items[lastInsertion].getData()) == 0){
						
						
						if (items[lastInsertion].getData().equals(element)) {
							
							refresh(element);
							newItem = false;
						}
						lastInsertion ++;
					}
					
					if(lastInsertion == items.length)
						index = -1;
					else
						index = lastInsertion + i; 					
				}
			}
			if(newItem)
				createTreeItem(widget, element, index);		
		}
    }
	
    /**
     * See if element is the data of one of the elements in 
     * items.
     * @param items