diff --git a/Userland/Libraries/LibGUI/Event.h b/Userland/Libraries/LibGUI/Event.h
index 7b13555eb72..b978daaa074 100644
--- a/Userland/Libraries/LibGUI/Event.h
+++ b/Userland/Libraries/LibGUI/Event.h
@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <AK/EnumBits.h>
 #include <AK/String.h>
 #include <AK/StringBuilder.h>
 #include <AK/Vector.h>
@@ -263,7 +264,7 @@ public:
     ByteString const& keymap() const { return m_keymap; }
 
 private:
-    const ByteString m_keymap;
+    ByteString const m_keymap;
 };
 
 class WMAddToQuickLaunchEvent : public WMEvent {
@@ -384,6 +385,8 @@ enum MouseButton : u8 {
     Forward = 16,
 };
 
+AK_ENUM_BITWISE_OPERATORS(MouseButton);
+
 class KeyEvent final : public Event {
 public:
     KeyEvent(Type type, KeyCode key, u8 map_entry_index, u8 modifiers, u32 code_point, u32 scancode)