Ever since I was prompted to download the update to Firefox 78.6.0 ESR on 12/15, Facebook Messenger will not load for me at all. I keep getting the message "A web page is slowing down your browser. What would you like to do?" It loads for me perfectly fine in Chrome, so this definitely appears to be a FF issue. I'm not having issues with any other site since the update. I've tried deleting my cookies and cache, I've tried opening FF with add-ons on disabled. I'm at a loss. It was working fine earlier in the day, and has not worked at all since the update. Any thoughts, advice, recommendations, anything would be greatly appreciated.