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: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/1e2d5d9ba4147d5ea3cc58789a6ba7f2426d0695/pref-applications.js/clean/suite/common/pref/pref-applications.js