After I posted thai language messege in long text I get "?" symbol , pls visit url below for this case

http://www.lcdsure.com/index.php?option=com_content&view=article&id=57

I've try to figured this out for a fews days but it make me more confuse because it will display right character in Name and Title box but wrong character in Text box.

my sql is UTF-8

I'm sorry to disturb you but many people from my country have problems about !joomlacomment like me.