Index: views.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/views/views.module,v
retrieving revision 1.322
diff -u -u -p -r1.322 views.module
--- views.module	16 Dec 2008 18:52:04 -0000	1.322
+++ views.module	15 Jan 2009 07:40:17 -0000
@@ -541,7 +541,11 @@ function views_get_module_apis() {
  * Include views .css files.
  */
 function views_add_css($file) {
-  drupal_add_css(drupal_get_path('module', 'views') . "/css/$file.css");
+  // We set preprocess to FALSE because we are adding the files conditionally,
+  // and we don't want to generate duplicate cache files.
+  // TODO: at some point investigate adding some files unconditionally and
+  // allowing preprocess. 
+  drupal_add_css(drupal_get_path('module', 'views') . "/css/$file.css", NULL, NULL, FALSE);
 }
 
 /**