Bug 292322 [Viewers] Tree view is removing + indicator when one of multiple children is removed.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
}
		Item[] items = getChildren(widget);
		for (int i = 0; i < items.length; i++) {
			Item item = items[i];
			Object data = item.getData();
			virtualRefreshExpandedItems(widget, item, data, i);
		}
	}
	/*
	 * 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) {
			
			
			if (item.getData(VIRTUAL_DISPOSE_KEY) == null) {
				item.setData(VIRTUAL_DISPOSE_KEY, Boolean.TRUE);
				item.addDisposeListener(new DisposeListener() {
					public void widgetDisposed(DisposeEvent e) {
						if (!treeIsDisposed) {
							Object data = item.getData();
							if (usingElementMap() && data != null) {
								unmapElement(data, item);
							}
						}
					}
				});