# WebExtensions - browser action with popup not working

**URL:** <https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788>\
**Category:** Development\
**Created:** [September 2, 2015, 10:01pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788 "2015-09-02T22:01:39Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![grb](https://avatars.discourse-cdn.com/v4/letter/g/47e85d/32.png) [@grb](https://discourse.mozilla.org/u/grb)\
**Post date:** [September 2, 2015, 10:01pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/1 "2015-09-02T22:01:39Z")

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CustomizableUI does not build the toolbar button, gives the message:  
[CustomizableUI] Custom widget with id … does not return a valid node

Problem appears to be: ext-browserAction.js:143, undeclared reference XUL\_NS

Tested in both Aurora and Nightly.

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**Author:** ![TheOne](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/theone/32/49872_2.png) [@TheOne](https://discourse.mozilla.org/u/TheOne)\
**Post date:** [September 2, 2015, 9:59pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/2 "2015-09-02T21:59:48Z")

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Adding @billm.

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**Author:** ![noitidart](https://avatars.discourse-cdn.com/v4/letter/n/9f8e36/32.png) [@noitidart](https://discourse.mozilla.org/u/noitidart)\
**Post date:** [September 2, 2015, 10:04pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/3 "2015-09-02T22:04:25Z")

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Show code please.  
I used CUI.jsm recently and it worked out fine here:

> <https://stackoverflow.com/questions/32135396/firefox-toolbarbutton-context-right-click-menu-on-toolbar/32156612#32156612>

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**Author:** ![grb](https://avatars.discourse-cdn.com/v4/letter/g/47e85d/32.png) [@grb](https://discourse.mozilla.org/u/grb)\
**Post date:** [September 2, 2015, 10:31pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/4 "2015-09-02T22:31:56Z")

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Just trying the example “beastify” from

> **[GitHub - mdn/webextensions-examples: Example Firefox add-ons created using the...](https://github.com/mdn/webextensions-examples)**
>
> Example Firefox add-ons created using the WebExtensions API

Note it is missing the “applications” property in the manifest. Maybe I’m doing something wrong.

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**Author:** ![wbamberg](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/wbamberg/32/30597_2.png) [@wbamberg](https://discourse.mozilla.org/u/wbamberg)\
**Post date:** [September 3, 2015, 5:28pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/5 "2015-09-03T17:28:51Z")

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No, you’re right. This is a known bug: [https://bugzilla.mozilla.org/show\_bug.cgi?id=1199842](https://bugzilla.mozilla.org/show_bug.cgi?id=1199842)

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**Author:** ![grb](https://avatars.discourse-cdn.com/v4/letter/g/47e85d/32.png) [@grb](https://discourse.mozilla.org/u/grb)\
**Post date:** [September 3, 2015, 9:27pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/6 "2015-09-03T21:27:58Z")

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Ahh thanks, I had searched Bugzilla for WebExtensions and came up with nothing.

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**Author:** ![billm](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@billm](https://discourse.mozilla.org/u/billm)\
**Post date:** [September 8, 2015, 5:20pm UTC](https://discourse.mozilla.org/t/webextensions-browser-action-with-popup-not-working/3788/7 "2015-09-08T17:20:31Z")

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This should be fixed now.