Actually look in the right place for subscriptions.

stepmania/src/MessageManager.cpp

@@ -218,6 +218,12 @@ void MessageManager::Broadcast( MessageID m ) const
 	Broadcast( MessageIDToString(m) );
 }
 
+bool MessageManager::IsSubscribedToMessage( IMessageSubscriber* pSubscriber, const RString &sMessage ) const
+{
+	SubscribersSet& subs = g_MessageToSubscribers[sMessage];
+	return subs.find( pSubscriber ) != subs.end();
+}	
+
 void IMessageSubscriber::ClearMessages( const RString sMessage )
 {
 }

stepmania/src/MessageManager.h

@@ -159,8 +159,6 @@ public:
 	//
 	void SubscribeToMessage( MessageID message ); // will automatically unsubscribe
 	void SubscribeToMessage( const RString &sMessageName ); // will automatically unsubscribe
-	inline bool IsSubscribedToMessage( const RString &sMessageName ) const { return find( m_vsSubscribedTo.begin(), m_vsSubscribedTo.end(), sMessageName ) != m_vsSubscribedTo.end(); }
-	inline bool IsSubscribedToMessage( MessageID message ) const { return IsSubscribedToMessage( MessageIDToString(message) ); }
 
 	void UnsubscribeAll();
 
@@ -182,6 +180,8 @@ public:
 	void Broadcast( Message &msg ) const;
 	void Broadcast( const RString& sMessage ) const;
 	void Broadcast( MessageID m ) const;
+	bool IsSubscribedToMessage( IMessageSubscriber* pSubscriber, const RString &sMessage ) const;
+	inline bool IsSubscribedToMessage( IMessageSubscriber* pSubscriber, MessageID message ) const { return IsSubscribedToMessage( pSubscriber, MessageIDToString(message) ); }
 
 	// Lua
 	void PushSelf( lua_State *L );

stepmania/src/ScreenSelect.cpp

@@ -29,7 +29,7 @@ void ScreenSelect::Init()
 	for( unsigned i = 0; i < m_asSubscribedMessages.size(); ++i )
 		MESSAGEMAN->Subscribe( this, m_asSubscribedMessages[i] );
 	// Only subscribe once.
-	if( !this->IsSubscribedToMessage(Message_PlayerJoined) )
+	if( !MESSAGEMAN->IsSubscribedToMessage(this, Message_PlayerJoined) )
 		this->SubscribeToMessage( Message_PlayerJoined );
 
 	//