IE9 + prototype + jQuery conflict

IE9 + prototype + jQuery conflict

Hi Everyone,
 
I've noticed this strange conflict when trying to get the width of a jQuery object in IE8/9 when prototypejs is also loaded.  I'm using the latest version of prototypejs. version 1.7
 
IE8/9 w/o prototype works correctly.
IE7 w/ prototype work correctly.
 
The object I'm trying to get the width from is a DIV with absolute positioning and a width of 500px in the style attribute.  It's called #INFO_DIALOG.
 
// supposed to return 500, but returns the WINDOW width.  same as jQuery(window).width();
// This does return 500 in IE7 with prototype or IE8/9 without prototype loaded.
jQuery("#INFO_DIALOG").width();
 
// returns 500px. works will all combinations
jQuery("#INFO_DIALOG").css("width");