Unlike other browsers mouse cursor is not changed when mouse pointer is placed on the corner of text area. In firefox case mouse cursor is changed with a resizer cursor. The changed cursor looks cool because user can recognize text area can be resized.
Created attachment 275662 [details] WIP
Created attachment 276234 [details] WIP
Fixing this via bug 210778. *** This bug has been marked as a duplicate of bug 210778 ***