User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0 Build ID: 20150125222008 Steps to reproduce: Write a basic sdk-based addon with ability to open a content panel and declaring a context menu item. Actual results: When opening the content panel, the console displays twice the message: JavaScript error: resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///hdd/home/mig/git/dwhelper/profile/extensions/%7Bb9db16a4-6edc-47ec-a1f4-b86292ed211d%7D.xpi!/bootstrap.js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/context-menu.js, line 690: TypeError: messageManager is undefined Panels and context menu open/close fine. Expected results: No error message should appear in the console.

Note that this behavior does not appear with Firefox 35, only with 36 beta

Could you try to find the regression range using mozregression? http://mozilla.github.io/mozregression/

Will have been caused by bug 1060138. Looks like the errors should be pretty harmless but should be straightforward enough to work around.

Paul, given Dave's input, can i assume you don't need the regression stuff ?

No, thank you.

I have the same problem testing on nighlty (making sure my extension is e10s compatible) and it throws the same error but on line 689: JavaScript error: resource://gre/modules/commonjs/toolkit/loader.js -> resource: //gre/modules/commonjs/sdk/context-menu.js, line 689: TypeError: messageManager is undefined this code should be enough to trigger the error: var self = require("sdk/self"); //create panel var panel = require("sdk/panel").Panel({ contentURL: self.data.url("panel.html") }); //add context menu var cm = require("sdk/context-menu"); cm.Item({ label: "test" });