diff --git a/frontend/document/document.lua b/frontend/document/document.lua
index e5ee097c8..fca96135b 100644
--- a/frontend/document/document.lua
+++ b/frontend/document/document.lua
@@ -252,7 +252,7 @@ end
 
 -- load implementations:
 
---require "document/pdfdocument"
---require "document/djvudocument"
+require "document/pdfdocument"
+require "document/djvudocument"
 require "document/koptdocument"
 require "document/credocument"