Fix for modular markdown preview admin#1066

CHANGELOG.md

@@ -1,3 +1,9 @@
+# v1.8.6
+## mm/dd/2018
+
+1. [](#bugfix)
+    * Force `html` for markdown preview [grav#2066](https://github.com/getgrav/grav/issues/2066)
+
 # v1.8.5
 ## 06/20/2018
 

classes/admincontroller.php

@@ -1863,6 +1863,7 @@ class AdminController extends AdminBaseController
 
             $this->preparePage($page, true);
             $page->header();
+            $page->templateFormat('html');
 
             // Add theme template paths to Twig loader
             $template_paths = $this->grav['locator']->findResources('theme://templates');