There isn't. That box is controlled by Facebook itself, and they don't allow us to manipulate it in anyway.
With that said, it looks like the following CSS change will make the right side of the box to not be hidden. In the plugins/system/jat3/jat3/base-themes/default/css/layout.css file, at line 12, you'll see:
.column { overflow: hidden; float: left; }Change that to:
.column { overflow:visible; float: left; }
That shouldn't have bad effects on other areas of the site, but obviously, test.
Hope that helps, and good luck!
Alex
change dimensions of send comment box.
