diff --git a/src/common/engine/namedef.h b/src/common/engine/namedef.h
index e2b31a1b6..121527192 100644
--- a/src/common/engine/namedef.h
+++ b/src/common/engine/namedef.h
@@ -278,6 +278,8 @@ xx(OptionMenuItemColorPicker)
 xx(OptionMenuItemStaticText)
 xx(OptionMenuItemStaticTextSwitchable)
 
+xx(Handler)
+
 xx(Color)
 
 xx(Mididevices)
diff --git a/src/common/menu/messagebox.cpp b/src/common/menu/messagebox.cpp
index 21f22d190..7c5938243 100644
--- a/src/common/menu/messagebox.cpp
+++ b/src/common/menu/messagebox.cpp
@@ -47,9 +47,10 @@ CVAR(Bool, m_quickexit, false, CVAR_ARCHIVE)
 typedef void(*hfunc)();
 DEFINE_ACTION_FUNCTION(DMessageBoxMenu, CallHandler)
 {
-	PARAM_PROLOGUE;
-	PARAM_POINTERTYPE(Handler, hfunc);
-	Handler();
+	PARAM_SELF_PROLOGUE(DMenu);
+	auto handler = reinterpret_cast<hfunc>(self->PointerVar<void>(NAME_Handler));
+	if (handler != nullptr)
+		handler();
 	return 0;
 }
 
@@ -68,7 +69,8 @@ DMenu *CreateMessageBoxMenu(DMenu *parent, const char *message, int messagemode,
 
 	IFVIRTUALPTRNAME(p, NAME_MessageBoxMenu, Init)
 	{
-		VMValue params[] = { p, parent, &namestr, messagemode, playsound, action.GetIndex(), reinterpret_cast<void*>(handler) };
+		p->PointerVar<void>(NAME_Handler) = reinterpret_cast<void*>(handler);
+		VMValue params[] = { p, parent, &namestr, messagemode, playsound, action.GetIndex() };
 		VMCall(func, params, countof(params), nullptr, 0);
 		return (DMenu*)p;
 	}
diff --git a/wadsrc/static/zscript/engine/ui/menu/messagebox.zs b/wadsrc/static/zscript/engine/ui/menu/messagebox.zs
index 52734cf04..32dce5038 100644
--- a/wadsrc/static/zscript/engine/ui/menu/messagebox.zs
+++ b/wadsrc/static/zscript/engine/ui/menu/messagebox.zs
@@ -35,7 +35,7 @@
 class MessageBoxMenu : Menu
 {
 	BrokenLines mMessage;
-	readonly internal voidptr Handler;
+	readonly voidptr Handler;
 	int mMessageMode;
 	int messageSelection;
 	int mMouseLeft, mMouseRight, mMouseY;
@@ -45,7 +45,7 @@ class MessageBoxMenu : Menu
 	int destWidth, destHeight;
 	String selector;
 
-	private native static void CallHandler(voidptr hnd);
+	native void CallHandler();
 
 
 	//=============================================================================
@@ -54,7 +54,7 @@ class MessageBoxMenu : Menu
 	//
 	//=============================================================================
 
-	virtual void Init(Menu parent, String message, int messagemode, bool playsound = false, Name cmd = 'None', voidptr native_handler = null)
+	virtual void Init(Menu parent, String message, int messagemode, bool playsound = false, Name cmd = 'None')
 	{
 		Super.Init(parent);
 		mAction = cmd;
@@ -95,7 +95,6 @@ class MessageBoxMenu : Menu
 		{
 			MenuSound ("menu/prompt");
 		}
-		Handler = native_handler;
 	}
 
 	//=============================================================================
@@ -164,7 +163,7 @@ class MessageBoxMenu : Menu
 		{
 			if (res) 
 			{
-				CallHandler(Handler);
+				CallHandler();
 			}
 			else
 			{