Winner! Winner! Winner! Chicken Dinner!!! This worked for me. In Big Sur, in Preferences, it says Dock & Menu Bar. I followed Scott's prompts, and everything is working normally now. Wow!
I just tested it both ways, with deleting cookies and without deleting cookies and both results ended with the same result: extra Firefox icon on the dock.
I have been dealing with this issue all day and have gotten used to it. Every time I close Firefox, I get a duplicate icon in my dock. But here is something odd, just minutes ago, I had both Firefox open and Spotify open on my desktop. I closed Firef...
