diff --git a/pkgs/desktops/xfce/panel-plugins/xfce4-whiskermenu-plugin.nix b/pkgs/desktops/xfce/panel-plugins/xfce4-whiskermenu-plugin.nix
index ff4e89a23cf..8ba542b398e 100644
--- a/pkgs/desktops/xfce/panel-plugins/xfce4-whiskermenu-plugin.nix
+++ b/pkgs/desktops/xfce/panel-plugins/xfce4-whiskermenu-plugin.nix
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
 
   preFixup = ''
     substituteInPlace $out/bin/xfce4-popup-whiskermenu \
-      --replace $out/bin/xfce4-panel ${xfce4panel}/bin/xfce4-panel
+      --replace $out/bin/xfce4-panel ${xfce4panel.out}/bin/xfce4-panel
   '';
 
   meta = {