Here is a very basic demo of what I'm trying to accomplish.
Open in Google Chrome: http://jsfiddle.net/8EbxG/4/
It should look like there's nothing there, except for a grey rectangle.
Now, open in IE9, or Firefox.
You will see an empty white rectangle contained within the larger grey one.
What do I need to do to get this looking like it does in chrome Chrome cross browser (I haven't even tested older IE, or Opera, or Safari)?
add this css:
#sb-caption:empty {display:none;}