Mine

in src/Commands/PCommandManager.h  

#ifndef COMMAND_MANAGER_H
#define COMMAND_MANAGER_H

#include <app/Message.h>
#include <support/List.h>
#include <support/KeyedVector.h>
#include <support/String.h>

#ifdef B_ZETA_VERSION_1_0_0
	#include <locale/Locale.h>
	#include <locale/LanguageNotifier.h>
#else
	#define _T(a) a
#endif 

#include "PCommand.h"
#include "BasePlugin.h"
#include "Indexer.h"
class PDocument;