More of a cosmetic issue here, but when signing in you can choose from options such as Google, Facebook, Yahoo and Stack Exchange. Now when clicking one of these, a highlight box is set around the clicked item. Unfortunately this makes all items to the right of it move up a couple of pixels, and it annoys me sooooo much.
Of course after you click it you are redirected to the corresponding login, but you can still see it a few seconds before it redirects, and if you go back a page it's also still highlighted.
Here's an image of the before- and after clicking the Google-button: