--- panels_tabs.module
+++ panels_tabs.module
@@ -35,12 +35,20 @@ function  panels_tabs_ctools_plugin_api($module, $api) {
 function panels_tabs_panels_pre_render($display, $renderer) {
   // Don't run if we are using legacy mode
   if (panels_tabs_style_version() == 2) {
-    $renderer->prepare();
-    foreach ($renderer->prepared['regions'] as $id => $region) {
-      if ($region['style']['name'] == 'tabs') {
-        foreach ($region['pids'] as $pid) {
-          $renderer->prepared['panes'][$pid]->region_style = 'tabs';
-        }
+    $tabs_regions = array();
+
+    // Find out which regions are using the tabs style and add to an array
+    foreach ($renderer->display->panel_settings as $region_id => $region) {
+      if ($region['style'] == 'tabs') {
+        $tabs_regions[] = $region_id;
+      }
+    }
+
+    // Go through all the panes and mark those that are in a tab region.
+    foreach ($renderer->display->content as $pane_id => $pane) {
+      if (in_array($pane->panel, $tabs_regions)) {
+        $tabs_regions[] = $region_id;
+        $renderer->display->content[$pane_id]->region_style = 'tabs';
       }
     }
   }