rem: if (visible) { var invertArrow = false;  if (item.firstChild.tw_invertArrow) invertArrow = true;  item.firstChild.lastChild.style.backgroundImage = invertArrow ? tw_menu_imageMenuArrowInvert : tw_menu_imageMenuArrow; } else item.firstChild.lastChild.style.backgroundImage = ""; 
add: var b = item.firstChild; var img = ""; if (visible) img = b.tw_invertArrow ? "url(?_twr_=menuArrowInvert.png)" : "url(?_twr_=menuArrow.png)"; if (b.style.backgroundImage != img) b.style.backgroundImage = img; 
context:     _setArrowVisible: function(item, visible) {        if (visible) {            var invertArrow = false;                        if (item.firstChild.tw_invertArrow)                invertArrow = true;                            item.firstChild.lastChild.style.backgroundImage = invertArrow ? tw_menu_imageMenuArrowInvert : tw_menu_imageMenuArrow;        } else            item.firstChild.lastChild.style.backgroundImage = "";    },    
meta: 5515	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5515/f1782c774313ba79c127ba5da30580c5ce1f4c32/Menu.js/buggy/src/thinwire/render/web/resources/Menu.js