diff --git a/extensions/transformiix/resources/buster/result-inspector.xul b/extensions/transformiix/resources/buster/result-inspector.xul
index c9bad9046e4a..a27594367724 100644
--- a/extensions/transformiix/resources/buster/result-inspector.xul
+++ b/extensions/transformiix/resources/buster/result-inspector.xul
@@ -36,7 +36,7 @@
    -
    - ***** END LICENSE BLOCK ***** -->
 
-<!DOCTYPE overlay [
+<!DOCTYPE window [
   <!ENTITY % dtd1 SYSTEM "chrome://inspector/locale/inspector.dtd"> %dtd1;
   <!ENTITY % dtd2 SYSTEM "chrome://inspector/content/util.dtd"> %dtd2;
 ]>