diff --git a/nix-os/desktopManagers/gnome.nix b/nix-os/desktopManagers/gnome.nix
index a6b878f..f3512b5 100644
--- a/nix-os/desktopManagers/gnome.nix
+++ b/nix-os/desktopManagers/gnome.nix
@@ -4,8 +4,8 @@ let
   maxThumbnails = config.programs.gnome.extensions.workspaceIndicator.maxThumbnails;
   workspaceIndicator = pkgs.gnomeExtensions.workspace-indicator.overrideAttrs {
     postPatch = ''
-      sed -i 's/const MAX_THUMBNAILS = 6;/const MAX_THUMBNAILS = ${maxThumbnails};/' extension.js
-    '';
+        sed -i 's/const MAX_THUMBNAILS = 6;/const MAX_THUMBNAILS = '${builtins.toString maxThumbnails}'/' extension.js
+      '';
   };
 in
 {