diff --git a/Phys/LoKiArrayFunctors/src/Components/DTFDict.cpp b/Phys/LoKiArrayFunctors/src/Components/DTFDict.cpp
index 2f7f93a8ee09371ab2c868b925575a9c7b8cb969..55f5c46bf258224a2649167121def88191fbe980 100644
--- a/Phys/LoKiArrayFunctors/src/Components/DTFDict.cpp
+++ b/Phys/LoKiArrayFunctors/src/Components/DTFDict.cpp
@@ -115,7 +115,7 @@ namespace LoKi {
         // printConstraints(std::cout);
 
         IDecayTreeFit*  myfitter  = fitter(); // from AuxDTFBase
-        StatusCode      sc        = myfitter->fit( p, vertex );
+        StatusCode      sc        = myfitter->fit( tree.head(), vertex );
         LHCb::Particle* prefitted = nullptr;
         if ( sc.isFailure() ) {
           // Hand an empty pointer to source and let it decide how to fill the