Index: thickbox.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/thickbox/thickbox.module,v
retrieving revision 1.18.2.17
diff -u -p -r1.18.2.17 thickbox.module
--- thickbox.module	24 Mar 2009 14:25:36 -0000	1.18.2.17
+++ thickbox.module	25 Aug 2009 22:27:48 -0000
@@ -91,7 +91,7 @@ function _thickbox_doheader() {
   $path = drupal_get_path('module', 'thickbox');
   drupal_add_css($path .'/thickbox.css');
   if (variable_get('thickbox_ie_css', 0) != 1) {
-    drupal_add_css($path .'/thickbox_ie.css');
+    drupal_set_html_head('<!--[if IE]><link type="text/css" rel="stylesheet" media="all" href="'. $path .'/thickbox_ie.css'.'" /><![endif]-->');
   }
 
   // Insert translated strings as javascript settings.