Stretchable reply box not working in Windows 7

[Electric2Shock]

And yes, I use Win7 x86.

The stretchable replybox of newthread.php and newreply.php that I used to experience on Windows XP now does not seem to be stretchable anymore in Windows 7 and Vista.

And the part of it that covers "Signature: Include your signature. (registered users only)" does not look neat.

Screenshot (Click to View)