rem: gTree.setAttribute("ref", "urn:mimetypes"); 
add: gList.setAttribute("ref", "urn:mimetypes"); 
context: function removeType(){  var titleMsg = gPrefApplicationsBundle.getString("removeHandlerTitle");  var dialogMsg = gPrefApplicationsBundle.getString("removeHandler");  dialogMsg = dialogMsg.replace(/%n/g, "\n");  var promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(Components.interfaces.nsIPromptService);  var remove = promptService.confirm(window, titleMsg, dialogMsg);  if (remove) {    var uri = gTree.selectedItems[0].id;    var handlerOverride = new HandlerOverride(uri);    removeOverride(handlerOverride.mimeType);    gTree.setAttribute("ref", "urn:mimetypes");  }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/07d96867f11683becf5e1a6ca5e64e6a9324c957/pref-applications.js/buggy/xpfe/components/prefwindow/resources/content/pref-applications.js