Bug 126061 [Viewers] Need to document that virtual tables and trees ignore sorters and filters
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
Item item = items[i];
				Object data = item.getData();
				if (data != null) {
					virtualRefreshChildCounts(item, data);
				}
			}
		}
	}
	
	/*
	 * To unmap elements correctly, we need to register a dispose listener with
	 * the item if the tree is virtual.
	 */
	protected void mapElement(Object element, final Widget item) {
		super.mapElement(element, item);
		
		if ((getTree().getStyle() & SWT.VIRTUAL) != 0) {
			item.addDisposeListener(new DisposeListener(){
				public void widgetDisposed(DisposeEvent e) {
					if (!treeIsDisposed) {
						Object data = item.getData();
						if (usingElementMap() && data != null) {
							unmapElement(data, item);
						}
					}
				}});
		}
	}
}