This is a minor usability problem.

Steps to reproduce:

1. On Moodle.org, arrange for someone to send you a message.
2. Go any page on Moodle.org. You will get the grey bar at the bottom. *
3. Ctrl+click or Middle click on the link in the grey bar that is supposed to open the messaging UI, in order to get it to open in a new tab.

Expected result:

4a. Messaging UI opens in a new tab. Nothing happens in the original tab.

Actual result:

4b. Messaging UI opens in both the new tab and the old tab.

I see this in both Firefox on Windows and Mac, and in Safari on a Mac.

• As an aside, note that if the message you were sent is very long, the grey bar takes up most of the screen. It would be better if the contents was trimmed a bit.