User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:73.0) Gecko/20100101 Firefox/73.0

Steps to reproduce:

I accidentally closed Firefox, realized it immediately, and clicked the icon to re-open Firefox. Of course since Firefox takes a long time to shut down, it was still running in the background when I tried to restart it. So in this case it pops up a dialog box saying "Firefox is already running [Close Firefox] [Cancel]". The problem is those two buttons are not clear. In fact they do the opposite of their stated function. I wanted to the old Firefox that was still running in the background to finish shutting down, so I pressed the "Close Firefox" button. But instead of causing Firefox to shut down (close) like I told it to, it it caused Firefox to start up (open).

Actual results:

I pressed the [Close] button, and Firefox opened instead of closing.

Expected results:

The [Close Firefox] and [Cancel] buttons need to be reworded so that the button's wording matches the button's function. Please keep in mind that there may be two instances of Firefox trying to run.