diff --git a/pkgs/by-name/wi/windowmaker/dockapps/wmsm-app.nix b/pkgs/by-name/wi/windowmaker/dockapps/wmsm-app.nix
index 6becfce9578b..36b555a81dd4 100644
--- a/pkgs/by-name/wi/windowmaker/dockapps/wmsm-app.nix
+++ b/pkgs/by-name/wi/windowmaker/dockapps/wmsm-app.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation  (finalAttrs: {
 
   inherit (dockapps-sources) version src;
 
-  sourceRoot = "${src.name}/wmsm.app/wmsm";
+  sourceRoot = "${finalAttrs.src.name}/wmsm.app/wmsm";
 
   buildInputs = [
     libX11