Under "known issues" it has "For some users, scrolling in the main GMail window will be slower than usual (see 579260)"
I've noticed sometimes on YouTube too that videos won't load up the first time round, second time round... in what appears to be a random thing. Sometimes it works first time, sometimes not. The paranoid in me says that they do this on purpose alongside a "try chrome!" ad.
I still use FF out of habit, it "works" but Ive found Chrome to be faster.
I jumped straight from 15 to 18. No choice: I ran into one of those infernal sites that refuse even to try doing its thing if you're got the Wrong Browser.* And unfortunately it was a quasi-official function that I had no choice about. Otherwise I'd just have left the site after my second choice met the same message. Well, OK, I could have filled out the paper form, found a stamp and put it in snail mail. But who wants to do that?
So far I have no idea what if anything has changed, because while it was downloading I opened the previous day's logs, picked a likely UA string and told Safari to send it. Worked without a blip.
* Versions such-and-such of MSIE, Firefox, Chrome or-- so help me-- Safari for windows only.
<rant> Ridiculous ... I upgraded from 16 today after all the 'important notices' I've been getting, and tonight, working on a dev version of a site with the live one 'mirrored dynamically' I did 'something' and everything broke in the display ... So, I checked the live version to make sure I didn't mess up the live style sheet I was copying and pasting changes to, but everything looked fine.
A half an hour later, after copying and pasting the source code from the live version to the dev version and still seeing the display wrong, I finally quit FireFox and restarted ... What happened? The dev version worked Fine. The error was with FireFox ... Somehow it 'got stuck' in a wrong display. Huh? Seriously? ... Back to Safari if they don't stop with the Ridiculous update schedule that always seems to completely mess things up for a while when I finally decide to 'go with it' ... Talk about annoying. </rant>