You can still share a blocked site by using middle click

[obotisan]

Affected versions:

• Firefox 67.0

Affected Platforms:

• Windows 10 x64
• Ubuntu 18.04 x64
• macOS 10.13

Prerequisites:

• Have the facebook_container-1.7.3 add-on installed.

Steps to reproduce:

1. Go to a site that has the share button locked, for example this link.
2. On the right side of the screen click by using middle-click on the Share button.

Expected result:

• The facebook container prompt will appear.

Actual result:

• A new tab is open and you are able to share the post, even though the button should be locked..

Notes:

• This issue is reproducing on a lot of other sites, too.
• Please see the attached screencast with the issue:
  

[maxxcrawford]

Leaving a link for myself (or anyone who tackles this issue):
https://stackoverflow.com/questions/1795734/triggering-onclick-event-using-middle-click

[maxxcrawford]

Duplicate of #375