Index: quicktabs.module
===================================================================
--- quicktabs.module	(revision 136)
+++ quicktabs.module	(working copy)
@@ -648,7 +648,7 @@
  * Helper function to determine active tab from the url.
  */
 function _quicktabs_get_active_tab($quicktabs) {
-  $active_tab = isset($quicktabs['default_tab']) ? $quicktabs['default_tab'] : key($quicktabs['tabs']);
+  $active_tab = isset($quicktabs['default_tab']) && $quicktabs['default_tab'] !== false ? $quicktabs['default_tab'] : key($quicktabs['tabs']);
   $active_tab = isset($_GET['quicktabs_'. $quicktabs['machine_name']]) ? $_GET['quicktabs_'. $quicktabs['machine_name']] : $active_tab;
   if (isset($active_tab) && isset($quicktabs['tabs'][$active_tab])) {
     return $active_tab;