Script error when composing message

[italways]

On Compose page, I got a yellow excalmatory mark icon on IE status, click the icon it shows :

---

Line:495
Char:4
Error:Object doesn't support this property or method
Code:0

---

I also found the text I input in the compose input box is very very small, while it becomes normal when I sent this text message out or the text display on Inbox page, it should get the "textarea" class from my wpmu css, but it seems not, I wonder is it related to the above error.

furthermore, the same "small text" problem happens when you reply a message, but without the yellow excalmatory mark icon on IE status.

[apeatling]

IE testing has not taken place yet. This will be fixed up when browser testing is done.