Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.756.2.11
diff -u -p -r1.756.2.11 common.inc
--- includes/common.inc	5 May 2008 21:40:46 -0000	1.756.2.11
+++ includes/common.inc	9 May 2008 16:27:23 -0000
@@ -1712,6 +1712,8 @@ function drupal_get_css($css = NULL) {
         // If the theme supplies its own style using the name of the module style, skip its inclusion.
         // This includes any RTL styles associated with its main LTR counterpart.
         if ($type == 'module' && in_array(str_replace('-rtl.css', '.css', basename($file)), $theme_styles)) {
+          // Unset the file to prevent its inclusion when CSS aggregation is enabled.
+          unset($types[$type][$file]);
           continue;
         }
         if (!$preprocess || !($is_writable && $preprocess_css)) {