diff --git a/components/style/properties/shorthands/box.mako.rs b/components/style/properties/shorthands/box.mako.rs
index 7b4ce131922..351b8cec606 100644
--- a/components/style/properties/shorthands/box.mako.rs
+++ b/components/style/properties/shorthands/box.mako.rs
@@ -464,11 +464,13 @@ ${helpers.two_properties_shorthand(
         };
 
         // Make sure that the initial value matches the values for the
-        // longhands, just for general sanity.
+        // longhands, just for general sanity.  `zoom: 1` and `zoom: 0` are
+        // ignored, see [1][2]. They are just hack for the "has layout" mode on
+        // IE.
         //
-        // FIXME: Should we just do this for the "normal" case? Seems weird
-        // either way, so maybe not?
-        Ok(if zoom.get() == 1.0 {
+        // [1]: https://bugs.webkit.org/show_bug.cgi?id=18467
+        // [2]: https://bugzilla.mozilla.org/show_bug.cgi?id=1593009
+        Ok(if zoom.get() == 1.0 || zoom.get() == 0.0 {
             expanded! {
                 transform: Transform::none(),
                 transform_origin: TransformOrigin::initial_value(),