Footon, I have reported this issue two weeks ago and they uploaded patch yesterday. I applied the patch and it seams the issue is fixed. I also changed the new PM notification.
Ctrl + F5 required in order to force the browser to load the new style.
Regrading to the Re: Topic Title , I also didn't liked it at first, but I see it useful now.
This forum version has a better theme structure that provides a responsive view on mobile devices and on smaller screens. It keeps the old look on purpose on a PC screen, but it zooms properly on smaller screens. It was practically impossible to read the forum on a mobile phone before.
No horizontal scrolling needed anymore.