I am trying to post a bug report here that contains some Arabic text (it's an RTL issue). You can read the text of the bug report at this pastebin link: http://pastebin.com/raw.php?i=HCUHQdb8.
When I do so, I get one of those red boxes at the right side of the textarea that tells me my post cannot be submitted. You can read the text of that red box at this pastebin link: http://pastebin.com/raw.php?i=NT83uzFv. (Pastebin links so I don't trip the validator in this post, of course.)
I can't read Arabic, so I don't know what the problematic string says (though a helpful anonymous editor informs me that it says: "Hakeem/Hakim the lost Philosopher"), but I don't see any reason why any particular string of Arabic text would be excluded by the validation machinery.
In case this is a client-side issue - I'm using Chrome 35 on Windows 7.