diff --git a/components/style/values/specified/box.rs b/components/style/values/specified/box.rs
index fa5d5a2d43a..dbdaf2048a2 100644
--- a/components/style/values/specified/box.rs
+++ b/components/style/values/specified/box.rs
@@ -104,6 +104,8 @@ pub enum DisplayInside {
     #[cfg(feature = "gecko")]
     MozGridLine,
     #[cfg(feature = "gecko")]
+    MozStack,
+    #[cfg(feature = "gecko")]
     MozDeck,
     #[cfg(feature = "gecko")]
     MozPopup,
@@ -227,6 +229,8 @@ impl Display {
     #[cfg(feature = "gecko")]
     pub const MozGridLine: Self = Self::new(DisplayOutside::XUL, DisplayInside::MozGridLine);
     #[cfg(feature = "gecko")]
+    pub const MozStack: Self = Self::new(DisplayOutside::XUL, DisplayInside::MozStack);
+    #[cfg(feature = "gecko")]
     pub const MozDeck: Self = Self::new(DisplayOutside::XUL, DisplayInside::MozDeck);
     #[cfg(feature = "gecko")]
     pub const MozPopup: Self = Self::new(DisplayOutside::XUL, DisplayInside::MozPopup);
@@ -616,6 +620,8 @@ impl Parse for Display {
             #[cfg(feature = "gecko")]
             "-moz-grid-line" if moz_display_values_enabled(context) => Display::MozGridLine,
             #[cfg(feature = "gecko")]
+            "-moz-stack" if moz_display_values_enabled(context) => Display::MozStack,
+            #[cfg(feature = "gecko")]
             "-moz-deck" if moz_display_values_enabled(context) => Display::MozDeck,
             #[cfg(feature = "gecko")]
             "-moz-popup" if moz_display_values_enabled(context) => Display::MozPopup,