设置右键菜单
var myContextMenu:ContextMenu = new ContextMenu();
var item:ContextMenuItem = new ContextMenuItem("Design by:Shenhuait.com");
myContextMenu.customItems.push(item);
myContextMenu.hideBuiltInItems();
this.contextMenu = myContextMenu;
item.addEventListener(ContextMenuEvent.MENU_ITEM_SELECT,gotoDesign);