diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 59f3dff96ff..7bec5361348 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -2340,7 +2340,7 @@ ${helpers.single_keyword("-moz-appearance",
                             -moz-window-titlebar-maximized
                          """,
                          gecko_ffi_name="mAppearance",
-                         gecko_constant_prefix="NS_THEME",
+                         gecko_constant_prefix="ThemeWidgetType_NS_THEME",
                          products="gecko",
                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-appearance)",
                          animation_value_type="none")}