rem: return aElem.ownerDocument .defaultView .getComputedStyle(aElem, "").getPropertyValue(aProp); 
add: return elem.ownerDocument .defaultView .getComputedStyle(aElem, "").getPropertyValue(prop); 
context:   getComputedStyle: function(aElem, aProp) {    return aElem.ownerDocument                .defaultView                .getComputedStyle(aElem, "").getPropertyValue(aProp);  },
meta: 10520	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10520/e01f3facfe5a994e9967aeafea72d1fe9e30661d/nsContextMenu.js/buggy/browser/base/content/nsContextMenu.js