diff --git a/addons/web_editor/static/src/js/backend.js b/addons/web_editor/static/src/js/backend.js
index 062b91bd7a2..0b0851a19f5 100644
--- a/addons/web_editor/static/src/js/backend.js
+++ b/addons/web_editor/static/src/js/backend.js
@@ -295,7 +295,9 @@ var FieldTextHtml = widget.extend({
             }
         } else {
             this.$content.html(value);
-            this.$iframe.css("height", (this.$body.height()+20) + "px");
+            if (this.$iframe[0].contentWindow) {
+                this.$iframe.css("height", (this.$body.height()+20) + "px");
+            }
         }
     },
     is_false: function() {