I'm running two displays and whenever the Opera window is on my RIGHT display, the dropdown menus for folders in the bookmarks bar show up on the rightmost edge of the LEFT display. This seems to only happen when running dual displays with the LEFT display set as the primary (the one with the menubar in System Preferences > Displays > Arrangement). If I make the right display the primary, it works as it should on BOTH displays. Also if I set the left display to a lower resolution, the menus then appear on the correct display, but in the wrong position -- but again, only on the RIGHT display. Not a major issue, but a pretty ugly-looking one!

Edit: Here's a screenshot of the problem:
http://i.imgur.com/s4CoKdn.jpg

It's not a big deal since I can just click through to the theme creator's site and preview there, but it'd be great to know what's causing it so I can prevent it happening on my own sites. It feels like a script hanging, but there doesn't seem to be any way to tell what's really going on.

Apparently Opera updated itself recently, and now it hangs when previewing themes on wordpress.org. It says it's version 28.0.1750.40.

I've confirmed it happens on both Win 7 and Mac 10.10. See for yourself, just go to wordpress.org/themes, click any theme and click preview.

Nothing is reported in the console, and the process for the affected tab sits at 100+% CPU. I can sometimes close the tab normally, but other times I have to kill the process to get it to close. Not really sure what could have changed to cause this. It worked fine before the update.