Text fields

Is it possible to make the text fields use the available screen space rather than a fixed size?

Like n the screenshots,the space is being wasted.

In IE7 on Vista

http://img167.imageshack.us/img167/336/clipboard01mc5.th.jpg

In Opera,also in Vista

http://img167.imageshack.us/img167/2618/clipboard02hd0.th.jpg

Yes, that would be a lovely addition, kinda like how it is when you click edit on an already posted post.