diff --git a/lib/editor/tinymce/lib.php b/lib/editor/tinymce/lib.php
index b0f3bf00a4e..5d448ac8314 100644
--- a/lib/editor/tinymce/lib.php
+++ b/lib/editor/tinymce/lib.php
@@ -67,7 +67,11 @@ class tinymce_texteditor extends texteditor {
 
     public function use_editor($elementid, array $options=null, $fpoptions=null) {
         global $PAGE;
-        $PAGE->requires->js('/lib/editor/tinymce/tiny_mce/'.$this->version.'/tiny_mce.js');
+        if (debugging('', DEBUG_DEVELOPER)) {
+            $PAGE->requires->js('/lib/editor/tinymce/tiny_mce/'.$this->version.'/tiny_mce_src.js');
+        } else {
+            $PAGE->requires->js('/lib/editor/tinymce/tiny_mce/'.$this->version.'/tiny_mce.js');
+        }
         $PAGE->requires->js_init_call('M.editor_tinymce.init_editor', array($elementid, $this->get_init_params($elementid, $options)), true);
         if ($fpoptions) {
             $PAGE->requires->js_init_call('M.editor_tinymce.init_filepicker', array($elementid, $fpoptions), true);