rem: var updatesView = document.getElementById("updatesView"); updatesView.setAttribute("showcompletedupdates", checkbox.checked); 
add: this._updatesView.setAttribute("showcompletedupdates", checkbox.checked); 
context:   showCompletedUpdatesChanged: function(checkbox) {    var updatesView = document.getElementById("updatesView");    updatesView.setAttribute("showcompletedupdates", checkbox.checked);  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/d56af314aec4dbc7fed1957ca30860c8f442a318/updates.js/buggy/toolkit/mozapps/update/content/updates.js