diff --git a/components/style/style_adjuster.rs b/components/style/style_adjuster.rs
index 5e66e91e894..31028f98571 100644
--- a/components/style/style_adjuster.rs
+++ b/components/style/style_adjuster.rs
@@ -152,63 +152,6 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
         }
     }
 
-    /// https://html.spec.whatwg.org/multipage/#inert-subtrees
-    ///
-    ///    If -moz-inert is applied then add:
-    ///        -moz-user-focus: none;
-    ///        -moz-user-input: none;
-    ///        -moz-user-modify: read-only;
-    ///        user-select: none;
-    ///        pointer-events: none;
-    ///        cursor: default;
-    ///
-    /// NOTE: dialog:-moz-topmost-modal-dialog is used to override above
-    /// rules to remove the inertness for the topmost modal dialog.
-    ///
-    /// NOTE: If this or the pointer-events tweak is removed, then
-    /// minimal-xul.css and the scrollbar style caching need to be tweaked.
-    #[cfg(feature = "gecko")]
-    fn adjust_for_inert(&mut self) {
-        use crate::values::specified::ui::CursorKind;
-        use crate::values::specified::ui::UserSelect;
-        use properties::longhands::_moz_inert::computed_value::T as Inert;
-        use properties::longhands::_moz_user_focus::computed_value::T as UserFocus;
-        use properties::longhands::_moz_user_input::computed_value::T as UserInput;
-        use properties::longhands::_moz_user_modify::computed_value::T as UserModify;
-        use properties::longhands::cursor::computed_value::T as Cursor;
-        use properties::longhands::pointer_events::computed_value::T as PointerEvents;
-
-        let needs_update = {
-            let ui = self.style.get_inherited_ui();
-            if ui.clone__moz_inert() == Inert::None {
-                return;
-            }
-
-            ui.clone__moz_user_focus() != UserFocus::None ||
-                ui.clone__moz_user_input() != UserInput::None ||
-                ui.clone__moz_user_modify() != UserModify::ReadOnly ||
-                ui.clone_pointer_events() != PointerEvents::None ||
-                ui.clone_cursor().keyword != CursorKind::Default ||
-                ui.clone_cursor().images != Default::default()
-        };
-
-        if needs_update {
-            let ui = self.style.mutate_inherited_ui();
-            ui.set__moz_user_focus(UserFocus::None);
-            ui.set__moz_user_input(UserInput::None);
-            ui.set__moz_user_modify(UserModify::ReadOnly);
-            ui.set_pointer_events(PointerEvents::None);
-            ui.set_cursor(Cursor {
-                images: Default::default(),
-                keyword: CursorKind::Default,
-            });
-        }
-
-        if self.style.get_ui().clone_user_select() != UserSelect::None {
-            self.style.mutate_ui().set_user_select(UserSelect::None);
-        }
-    }
-
     /// Whether we should skip any item-based display property blockification on
     /// this element.
     fn skip_item_display_fixup<E>(&self, element: Option<E>) -> bool
@@ -909,7 +852,6 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
         #[cfg(feature = "gecko")]
         {
             self.adjust_for_appearance(element);
-            self.adjust_for_inert();
             self.adjust_for_marker_pseudo();
         }
         self.set_bits();