Index: includes/display-render.inc
===================================================================
--- includes/display-render.inc	(revision 3062)
+++ includes/display-render.inc	(working copy)
@@ -8,6 +8,44 @@
  */
 
 /**
+ * Given a full layout structure and a content array, render a panel display.
+ * @render
+ */
+function panels_render_layout($layout, $content, $css_id = NULL, $settings = array(), $display = NULL) {
+  if (!empty($layout['css'])) {
+    if (file_exists(path_to_theme() . '/' . $layout['css'])) {
+      drupal_add_css(path_to_theme() . '/' . $layout['css']);
+    }
+    else {
+      drupal_add_css($layout['path'] . '/' . $layout['css']);
+    }
+  }
+  // This now comes after the CSS is added, because panels-within-panels must
+  // have their CSS added in the right order; inner content before outer content.
+
+  // If $content is an object, it's a $display and we have to render its panes.
+  if (is_object($content)) {
+    $display = $content;
+    if (empty($display->cache['method'])) {
+      $content = panels_render_panes($display);
+    }
+    else {
+      $cache = panels_get_cached_content($display, $display->args, $display->context);
+      if ($cache === FALSE) {
+        $cache = new panels_cache_object();
+        $cache->set_content(panels_render_panes($display));
+        panels_set_cached_content($cache, $display, $display->args, $display->context);
+      }
+      $content = $cache->content;
+    }
+  }
+
+  $output = theme($layout['theme'], check_plain($css_id), $content, $settings, $display);
+
+  return $output;
+}
+
+/**
  * Render the administrative layout of a display.
  *
  * This is used for the edit version, so that layouts can have different