Ticket #23509: 23509-refreshed.diff

wp-includes/theme.php

@@ -1750 +1750 @@
                 }());
         </script>
         <?php
+}
+
+/**
+ * Returns true if the site is being previewed in the Customizer
+ *
+ * @since  3.8.0
+ * @return bool
+ */
+function is_customizer() {
+        global $wp_customize;
+        return is_a( $wp_customize, 'WP_Customize_Manager' ) && $wp_customize->is_preview();
 }
+ No newline at end of file