diff --git a/app/views/shop/products/_form.html.haml b/app/views/shop/products/_form.html.haml
index 0574822129..01e3b5ef19 100644
--- a/app/views/shop/products/_form.html.haml
+++ b/app/views/shop/products/_form.html.haml
@@ -13,7 +13,7 @@
     %form{action: cart_path}
       .small-12.medium-4.large-3.columns
         %input.button.primary.right.add_to_cart{type: :submit, value: "Your shopping cart",
-        "ng-disabled" => "!Cart.dirty"}
+        "ng-disabled" => "Cart.dirty"}
 
   %div.pad-top{bindonce: true}
     %product.animate-repeat{"ng-controller" => "ProductNodeCtrl",
@@ -42,5 +42,5 @@
     .small-12.columns
       %form{action: cart_path}
         %input.button.primary.right.add_to_cart{type: :submit, value: "Your shopping cart",
-        "ng-disabled" => "!Cart.dirty"}
+        "ng-disabled" => "Cart.dirty"}