I always use ‘O’ (rather than clicking with the mouse) to open the current story in a new tab. Before today, this would open the story in a new tab and switch to the new tab immediately. (In Firefox, I have enabled the option “When you open a link, image or media in a new tab, switch to it immediately”.) But today this stopped working. The story is opened in a new tab, but focus is not switched to the new tab.
If I click on the story with the mouse, then it works as expected. The problem is only with the keyboard shortcut (‘O’ or ‘V’).