Ok yesterday my Internet access speed was very slow, maybe due to heavy rain the past few days.
Then today, Yahoo Mail stopped working:
After I updated FF, I couldn't switch or close tabs! In the future, for any problems like this, the first response is to disable all add-ons.
So I updated TabMixPlus, and it worked.
But my tabs are all now the Title Bar colour and I can't read the text! Protip: you have to enable FF's Title Bar, then all the tabs will return to grey. Call me old-fashioned, I insist on a Menu Bar.
Then I spent some time customising my tab colours.
Yahoo Mail still doesn't work. I thought it might be me because it stopped working for a few minutes this month, but lots of people on Twitter are having this problem, so it's Yahoo. Twitter is great for seeing if you're the only one with this problem.