diff --git a/Userland/Libraries/LibWeb/HTML/Navigable.h b/Userland/Libraries/LibWeb/HTML/Navigable.h
index f8f9f610d7..3468303f94 100644
--- a/Userland/Libraries/LibWeb/HTML/Navigable.h
+++ b/Userland/Libraries/LibWeb/HTML/Navigable.h
@@ -66,6 +66,8 @@ public:
     JS::GCPtr<TraversableNavigable> traversable_navigable() const;
     JS::GCPtr<TraversableNavigable> top_level_traversable();
 
+    virtual bool is_top_level_traversable() const { return false; }
+
     enum class WindowType {
         ExistingOrNone,
         NewAndUnrestricted,
diff --git a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
index 6f46dcb577..d4f82af2a3 100644
--- a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
+++ b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
@@ -23,7 +23,7 @@ public:
 
     virtual ~TraversableNavigable() override;
 
-    bool is_top_level_traversable() const;
+    virtual bool is_top_level_traversable() const override;
 
     int current_session_history_step() const { return m_current_session_history_step; }
     Vector<JS::NonnullGCPtr<SessionHistoryEntry>>& session_history_entries() { return m_session_history_entries; }