else handlerInfo.preferredApplicationHandler = null; 
  onSelectAction: function(event) {    var actionItem = event.originalTarget;    var typeItem = this._list.selectedItem;    var handlerInfo = this._handledTypes[typeItem.type];    if (actionItem.hasAttribute("alwaysAsk")) {      handlerInfo.alwaysAskBeforeHandling = true;    }    else if (actionItem.hasAttribute("action")) {      let action = parseInt(actionItem.getAttribute("action"));      // Set the plugin state if we're enabling or disabling a plugin.      if (action == kActionUsePlugin)        handlerInfo.enablePluginType();      else if (handlerInfo.plugin && !handlerInfo.isDisabledPluginType)        handlerInfo.disablePluginType();      // Set the preferred application handler.      // FIXME: consider leaving the existing preferred app in the list      // when we set the preferred action to something other than useHelperApp      // so that legacy datastores that don't have the preferred app in the list      // of possible apps still include the preferred app in the list of apps      // the user can use to handle the type.  Filed as bug 395140.      if (action == Ci.nsIHandlerInfo.useHelperApp)        handlerInfo.preferredApplicationHandler = actionItem.handlerApp;      else        handlerInfo.preferredApplicationHandler = null;      // Set the "always ask" flag.      handlerInfo.alwaysAskBeforeHandling = false;      // Set the preferred action.      handlerInfo.preferredAction = action;    }    handlerInfo.store();    // Update the action label so it says the right thing once this type item    // is no longer selected.    typeItem.setAttribute("actionDescription",                          this._describePreferredAction(handlerInfo));  },
5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/5872/216ac11faf6eba4e2e267082510b51e548472508/applications.js/buggy/browser/components/preferences/applications.js