diff -Naur reference/lib.php new/lib.php
--- reference/lib.php	2009-01-09 10:31:16.000000000 -0800
+++ new/lib.php	2009-01-09 10:32:57.000000000 -0800
@@ -84,7 +84,8 @@
         // get current group only when really needed
 
     /// Set up things for a HTML editor if it's needed
-        if ($this->usehtmleditor = can_use_html_editor()) {
+        $quickgrade = get_user_preferences('assignment_quickgrade', 0);
+        if ($this->usehtmleditor = can_use_html_editor() && (!$quickgrade)) {
             $this->defaultformat = FORMAT_HTML;
         } else {
             $this->defaultformat = FORMAT_MOODLE;