rem: openNewTabWith(frameURL, null, null, null, false, makeURI(doc.referrer)); 
add: openNewTabWith(frameURL, null, null, null, false, referrer ? makeURI(referrer) : null); 
context:   openFrameInTab: function() {    var doc = this.target.ownerDocument;    var frameURL = doc.documentURIObject.spec;    openNewTabWith(frameURL, null, null, null, false, makeURI(doc.referrer));  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/e66675cbb70c2a822c4facd84a8da15d0104fda5/nsContextMenu.js/clean/browser/base/content/nsContextMenu.js