Links from settings menu are opened twice

[madalincm]

Affected Platforms:

• Windows 10 (64-bit)
• Mac 10.14.2

Precondition

• Secure proxy is installed and the user is logged in.

Steps to reproduce

1. Go to about:Addons and remove the Secure Proxy add-on. Do not refresh the page
2. Install the Secure proxy add-on via drag&drop
3. Go back to about:addons and click the Undo button from the "Firefox Private Network has been removed." section
4. Click on the Secure Proxy icon and go to the settings menu
   5 Click on the following links: Help & Support, Leave Feedback, Privacy Policy, Terms & conditions, Cloudflare

Expected result

• Each link opens the page in a single tab

Actual result:

• Each link opens two distinct tabs with the same page

Notes

Screencast for this issue:

[bakulf]

@mixedpuppy is this an addon bug or a platform one?
It seems that we have 2 listeners for the UI events.