diff --git a/src/frontends/controllers/ControlDocument.cpp b/src/frontends/controllers/ControlDocument.cpp
index 701ff89cd9..7d5544d339 100644
--- a/src/frontends/controllers/ControlDocument.cpp
+++ b/src/frontends/controllers/ControlDocument.cpp
@@ -79,9 +79,9 @@ BufferParams & ControlDocument::params() const
 }
 
 
-int ControlDocument::id() const
+BufferId ControlDocument::id() const
 {
-	return (int) &kernel().buffer();
+	return &kernel().buffer();
 }
 
 
diff --git a/src/frontends/controllers/ControlDocument.h b/src/frontends/controllers/ControlDocument.h
index 03ff4eebe4..71f7d01122 100644
--- a/src/frontends/controllers/ControlDocument.h
+++ b/src/frontends/controllers/ControlDocument.h
@@ -23,6 +23,9 @@ class TextClass;
 
 namespace frontend {
 
+///
+typedef void const * BufferId;
+
 /** A controller for Document dialogs.
  */
 class ControlDocument : public Dialog::Controller {
@@ -50,7 +53,7 @@ public:
 	///
 	BufferParams & params() const;
 	///
-	int id() const;
+	BufferId id() const;
 	///
 	void setLanguage() const;
 	///
diff --git a/src/frontends/qt4/QDocument.cpp b/src/frontends/qt4/QDocument.cpp
index 0cf28596ea..07bf99ca27 100644
--- a/src/frontends/qt4/QDocument.cpp
+++ b/src/frontends/qt4/QDocument.cpp
@@ -112,7 +112,7 @@ PreambleModule::PreambleModule(): current_id_(0)
 }
 
 
-void PreambleModule::update(BufferParams const & params, int id)
+void PreambleModule::update(BufferParams const & params, BufferId id)
 {
 	QString preamble = toqstr(params.preamble);
 	// Nothing to do if the params and preamble are unchanged.
diff --git a/src/frontends/qt4/QDocument.h b/src/frontends/qt4/QDocument.h
index a44e6d3598..58a1754bc5 100644
--- a/src/frontends/qt4/QDocument.h
+++ b/src/frontends/qt4/QDocument.h
@@ -144,12 +144,15 @@ private:
 };
 
 
+typedef void const * BufferId;
+
+
 class PreambleModule : public UiWidget<Ui::PreambleUi>
 {
 	Q_OBJECT
 public:
 	PreambleModule();
-	void update(BufferParams const & params, int id);
+	void update(BufferParams const & params, BufferId id);
 	void apply(BufferParams & params);
 
 Q_SIGNALS:
@@ -161,9 +164,9 @@ protected:
 	void on_preambleTE_textChanged() { changed(); }
 
 private:
-	typedef std::map<int, std::pair<int,int> > Coords;
+	typedef std::map<BufferId, std::pair<int,int> > Coords;
 	Coords preamble_coords_;
-	int current_id_;
+	BufferId current_id_;
 };