--- sites/all/modules/switchtheme/switchtheme.module	2008-11-02 19:32:56.000000000 +0600
+++ sites/all/modules/switchtheme/switchtheme.module	2011-01-28 16:00:00.000000000 +0600
@@ -187,6 +187,7 @@ function switchtheme_switch_form_submit(
   elseif (user_access('switch theme')) {
     // Save the setting in the session for anonymous users.
     $_SESSION['custom_theme'] = $form_state['values']['theme'];
+    db_query("TRUNCATE TABLE {cache_page}");
   }
 }