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
} else if (widget instanceof TreeItem) {
    				((TreeItem)widget).clearAll(true);
    			}
    		}
    		return;
    	}
		super.internalRefreshStruct(widget, element, updateLabels);
	}
	/**
	 * Traverses the visible (expanded) part of the tree and updates child counts.
	 * @param widget
	 * @param element
	 * @param updateLabels
	 */
	private void virtualRefreshChildCounts(Widget widget, Object element) {
		ILazyTreeContentProvider lazyTreeContentProvider = (ILazyTreeContentProvider) getContentProvider();
		if (widget instanceof Tree || ((TreeItem)widget).getExpanded()) {
			
			if (element != null) {
				lazyTreeContentProvider.updateChildCount(element, getChildren(widget).length);
			} else {
				if (widget instanceof Tree) {
					((Tree)widget).setItemCount(0);
				} else {
					((TreeItem)widget).setItemCount(0);
				}
			}
			
			Item[] items = getChildren(widget);
			for (int i = 0; i < items.length; i++) {