diff --git a/src/support/mutex.cpp b/src/support/mutex.cpp
index 042c9b88cd..9f3babda27 100644
--- a/src/support/mutex.cpp
+++ b/src/support/mutex.cpp
@@ -40,22 +40,6 @@ Mutex::~Mutex()
 }
 
 
-// It makes no sense to copy the mutex,
-// each instance has its own QMutex,
-// therefore nothing to copy!
-// TODO review
-Mutex::Mutex(const Mutex&) : d(new Private)
-{
-}
-
-
-Mutex& Mutex::operator=(const Mutex&)
-{
-	return *this;
-}
-
-
-
 Mutex::Locker::Locker(Mutex* mtx) : mutex_(mtx)
 {
 	mutex_->d->qmutex_.lock();
diff --git a/src/support/mutex.h b/src/support/mutex.h
index ed3954f03f..5f34f7de51 100644
--- a/src/support/mutex.h
+++ b/src/support/mutex.h
@@ -21,6 +21,9 @@ namespace lyx {
 
 class Mutex
 {
+	/// noncopyable
+	Mutex(const Mutex&);
+	Mutex& operator=(const Mutex&);
 public:
 	Mutex();
 	~Mutex();
@@ -45,12 +48,6 @@ public:
 		Locker& operator=(const Locker& rhs);
 		Mutex* mutex_;
 	};
-	
-
-	// pseude-value semantic
-	// needed by GuiPrefs which makes a copy
-	Mutex(const Mutex&);
-	Mutex& operator=(const Mutex&);
 
 private:
 	struct Private;