Something

private static class HorizontalScrollHelper implements Listener {		public void handleEvent(Event e) {			Tree tree = ((Tree)e.widget);			TreeItem target = seek(tree.getItems(), e.y);						if (target != null) tree.showItem(target);		}		private TreeItem seek(TreeItem[] items, int y) {			TreeItem ret = null;			for (int i = 0; i < items.length; i++) {				TreeItem item = items[i];				int iBottom = item.getBounds().y+item.getBounds().height; 				if (iBottom > y) {					return item;				}								if (item.getExpanded()==true) {					ret = seek(items[i].getItems(), y);					if (ret != null) break;				}			}			return ret;		}	}