diff --git a/Phys/DecayTreeFitter/DecayTreeFitter/Fitter.h b/Phys/DecayTreeFitter/DecayTreeFitter/Fitter.h
index 7a331cdda8c9cc9b92a357505076209fac5c3a90..9c1090bc0eda6b7a810c09b4d4d4aaea4221c5d4 100644
--- a/Phys/DecayTreeFitter/DecayTreeFitter/Fitter.h
+++ b/Phys/DecayTreeFitter/DecayTreeFitter/Fitter.h
@@ -59,15 +59,17 @@ namespace DecayTreeFitter {
   public:
     // ========================================================================
     /// constructor from the particle (decay head)
-    Fitter( const LHCb::Particle& bc, const bool forceFitAll = true, const ITrackStateProvider* extrapolator = 0 );
+    Fitter( const LHCb::Particle& bc, const bool forceFitAll = true, const ITrackStateProvider* extrapolator = 0,
+            const bool useTrackTraj = true );
     /// constructor from the particle (decay head)
-    Fitter( const LHCb::Particle& bc, const ITrackStateProvider* extrapolator, const bool forceFitAll = true );
+    Fitter( const LHCb::Particle& bc, const ITrackStateProvider* extrapolator, const bool forceFitAll = true,
+            const bool useTrackTraj = true );
     /// constructor from the particle (decay head) and primary vertex
     Fitter( const LHCb::Particle& bc, const LHCb::VertexBase& pv, const bool forceFitAll = true,
-            const ITrackStateProvider* extrapolator = 0 );
+            const ITrackStateProvider* extrapolator = 0, const bool useTrackTraj = true );
     /// constructor from the particle (decay head) and primary vertex
     Fitter( const LHCb::Particle& bc, const LHCb::VertexBase& pv, const ITrackStateProvider* extrapolator,
-            const bool forceFitAll = true );
+            const bool forceFitAll = true, const bool useTrackTraj = true );
     /// destructor
     ~Fitter(); // destructor
     // ========================================================================
diff --git a/Phys/DecayTreeFitter/src/Configuration.h b/Phys/DecayTreeFitter/src/Configuration.h
index 8e8a1e4ae03fb72dfd7ba1890ce44c87ed6199c9..c0c8ded070ed25af02694a143f1c68042c206ee4 100644
--- a/Phys/DecayTreeFitter/src/Configuration.h
+++ b/Phys/DecayTreeFitter/src/Configuration.h
@@ -16,8 +16,8 @@ struct ITrackStateProvider;
 namespace DecayTreeFitter {
   class Configuration {
   public:
-    Configuration( bool forceFitAll = true, const ITrackStateProvider* stateprovider = 0 )
-        : m_forceFitAll( forceFitAll ), m_stateprovider( stateprovider ), m_useTrackTraj( true ) {}
+    Configuration( bool forceFitAll = true, const ITrackStateProvider* stateprovider = 0, bool useTrackTraj = true )
+        : m_forceFitAll( forceFitAll ), m_stateprovider( stateprovider ), m_useTrackTraj( useTrackTraj ) {}
 
     const ITrackStateProvider* stateProvider() const { return m_stateprovider; }
 
diff --git a/Phys/DecayTreeFitter/src/Fitter.cpp b/Phys/DecayTreeFitter/src/Fitter.cpp
index bc43d416bb87cd330b85b0c0366c6efc79d7e07a..4c3b5b7fe86f42bf2c0a6811de9b2ff06d9a3992 100644
--- a/Phys/DecayTreeFitter/src/Fitter.cpp
+++ b/Phys/DecayTreeFitter/src/Fitter.cpp
@@ -44,7 +44,8 @@ namespace DecayTreeFitter {
   // ==========================================================================
   // constructor from the particle (decay head)
   // ==========================================================================
-  Fitter::Fitter( const LHCb::Particle& bc, const bool forceFitAll, const ITrackStateProvider* extrapolator )
+  Fitter::Fitter( const LHCb::Particle& bc, const bool forceFitAll, const ITrackStateProvider* extrapolator,
+                  const bool useTrackTraj )
       : m_particle( &bc )
       , m_decaychain( 0 )
       , m_fitparams( 0 )
@@ -53,7 +54,7 @@ namespace DecayTreeFitter {
       , m_niter( -1 )
       , m_errCode( 0 )
       , m_extrapolator( const_cast<ITrackStateProvider*>( extrapolator ) ) {
-    Configuration config( forceFitAll, extrapolator );
+    Configuration config( forceFitAll, extrapolator, useTrackTraj );
     // build the tree
     m_decaychain = new DecayChain( bc, config );
     // allocate the fit parameters
@@ -62,7 +63,8 @@ namespace DecayTreeFitter {
   // ==========================================================================
   // constructor from the particle (decay head)
   // ==========================================================================
-  Fitter::Fitter( const LHCb::Particle& bc, const ITrackStateProvider* extrapolator, const bool forceFitAll )
+  Fitter::Fitter( const LHCb::Particle& bc, const ITrackStateProvider* extrapolator, const bool forceFitAll,
+                  const bool useTrackTraj )
       : m_particle( &bc )
       , m_decaychain( 0 )
       , m_fitparams( 0 )
@@ -71,7 +73,7 @@ namespace DecayTreeFitter {
       , m_niter( -1 )
       , m_errCode( 0 )
       , m_extrapolator( const_cast<ITrackStateProvider*>( extrapolator ) ) {
-    Configuration config( forceFitAll, extrapolator );
+    Configuration config( forceFitAll, extrapolator, useTrackTraj );
     // build the tree
     m_decaychain = new DecayChain( bc, config );
     // allocate the fit parameters
@@ -81,7 +83,7 @@ namespace DecayTreeFitter {
   // constructor from the particle (decay head) and primary vertex
   // ==========================================================================
   Fitter::Fitter( const LHCb::Particle& bc, const LHCb::VertexBase& pv, const bool forceFitAll,
-                  const ITrackStateProvider* extrapolator )
+                  const ITrackStateProvider* extrapolator, const bool useTrackTraj )
       : m_particle( &bc )
       , m_decaychain( 0 )
       , m_fitparams( 0 )
@@ -93,7 +95,7 @@ namespace DecayTreeFitter {
       , m_extrapolator( const_cast<ITrackStateProvider*>( extrapolator ) )
   //
   {
-    Configuration config( forceFitAll, extrapolator );
+    Configuration config( forceFitAll, extrapolator, useTrackTraj );
     m_decaychain = new DecayChain( bc, pv, config );
     m_fitparams  = new FitParams( m_decaychain->dim() );
   }
@@ -101,7 +103,7 @@ namespace DecayTreeFitter {
   // constructor from the particle (decay head) and primary vertex
   // ==========================================================================
   Fitter::Fitter( const LHCb::Particle& bc, const LHCb::VertexBase& pv, const ITrackStateProvider* extrapolator,
-                  const bool forceFitAll )
+                  const bool forceFitAll, const bool useTrackTraj )
       : m_particle( &bc )
       , m_decaychain( 0 )
       , m_fitparams( 0 )
@@ -113,7 +115,7 @@ namespace DecayTreeFitter {
       , m_extrapolator( const_cast<ITrackStateProvider*>( extrapolator ) )
   //
   {
-    Configuration config( forceFitAll, extrapolator );
+    Configuration config( forceFitAll, extrapolator, useTrackTraj );
     m_decaychain = new DecayChain( bc, pv, config );
     m_fitparams  = new FitParams( m_decaychain->dim() );
   }