rem: this._list.setAttribute("lastSelectedType", this._list.selectedItem.getAttribute("type")); 
add: if (this._list.selectedItem) this._list.setAttribute("lastSelectedType", this._list.selectedItem.getAttribute("type")); 
context:   onSelectionChanged: function() {    this._list.setAttribute("lastSelectedType",                            this._list.selectedItem.getAttribute("type"));  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/b838379102abc1ace7daa0072466c18546154355/applications.js/buggy/browser/components/preferences/applications.js