diff --git a/DDG4/include/DDG4/Geant4GeneratorAction.h b/DDG4/include/DDG4/Geant4GeneratorAction.h
index 8120a6e250c416ab7922e84ef76b062e0598a6cb..96b9f230d7e807270c706b11f7884059d051693b 100644
--- a/DDG4/include/DDG4/Geant4GeneratorAction.h
+++ b/DDG4/include/DDG4/Geant4GeneratorAction.h
@@ -88,11 +88,11 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4SharedGeneratorAction();
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Underlying object to be used during the execution of this thread
       virtual void use(Geant4GeneratorAction* action);
       /// User generator callback
-      virtual void operator()(G4Event* event);
+      virtual void operator()(G4Event* event)  override;
     };
 
     /// Concrete implementation of the Geant4 generator action sequence
@@ -127,9 +127,9 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4GeneratorActionSequence();
       /// Set or update client context
-      virtual void updateContext(Geant4Context* ctxt);
+      virtual void updateContext(Geant4Context* ctxt)  override;
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Get an action by name
       Geant4GeneratorAction* get(const std::string& name) const;
       /// Register primary particle generation callback. Types Q and T must be polymorph!
diff --git a/DDG4/include/DDG4/Geant4InputAction.h b/DDG4/include/DDG4/Geant4InputAction.h
index d894f61178a764580c0e647e3ddc614a9410ec4c..e6b07a0450ef5e2ef38ebdc0602d6cac10524e9b 100644
--- a/DDG4/include/DDG4/Geant4InputAction.h
+++ b/DDG4/include/DDG4/Geant4InputAction.h
@@ -189,7 +189,7 @@ namespace dd4hep  {
       /// Create particle vector
       Particles* new_particles() const { return new Particles; }
       /// Callback to generate primary particles
-      virtual void operator()(G4Event* event);
+      virtual void operator()(G4Event* event)   override;
     };
   }     /* End namespace sim   */
 }       /* End namespace dd4hep */
diff --git a/DDG4/include/DDG4/Geant4OutputAction.h b/DDG4/include/DDG4/Geant4OutputAction.h
index 78d3b771739c86d916c23d2565a579f7f18e615d..633cd9d9d5ca4a48648a6d987ec0a87acaaa76c4 100644
--- a/DDG4/include/DDG4/Geant4OutputAction.h
+++ b/DDG4/include/DDG4/Geant4OutputAction.h
@@ -68,12 +68,12 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4OutputAction();
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* ctxt);
+      virtual void configureFiber(Geant4Context* ctxt)  override;
 
       /// begin-of-event callback
-      virtual void begin(const G4Event* event);
+      virtual void begin(const G4Event* event)  override;
       /// End-of-event callback
-      virtual void end(const G4Event* event);
+      virtual void end(const G4Event* event)  override;
       /// Callback to initialize storing the Geant4 information
       virtual void beginRun(const G4Run* run);
       /// Callback to store the Geant4 run information
diff --git a/DDG4/include/DDG4/Geant4SensDetAction.h b/DDG4/include/DDG4/Geant4SensDetAction.h
index c70e714df5b1082e98dae5edf3fa1f6be8b51353..a192bc3667fd118642731679dc2feb380fcc98f7 100644
--- a/DDG4/include/DDG4/Geant4SensDetAction.h
+++ b/DDG4/include/DDG4/Geant4SensDetAction.h
@@ -367,7 +367,7 @@ namespace dd4hep {
       }
 
       /// Set or update client context
-      virtual void updateContext(Geant4Context* ctxt);
+      virtual void updateContext(Geant4Context* ctxt)  override;
 
       /// Called at construction time of the sensitive detector to declare all hit collections
       std::size_t defineCollections(Geant4ActionSD* sens_det);
diff --git a/DDG4/include/DDG4/Geant4SteppingAction.h b/DDG4/include/DDG4/Geant4SteppingAction.h
index 26f06542306650512f70704f9697d4aa100663a8..199c85efff81f92a83a3551042a5875e8faf9c25 100644
--- a/DDG4/include/DDG4/Geant4SteppingAction.h
+++ b/DDG4/include/DDG4/Geant4SteppingAction.h
@@ -79,11 +79,11 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4SharedSteppingAction();
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Underlying object to be used during the execution of this thread
       virtual void use(Geant4SteppingAction* action);
       /// User stepping callback
-      virtual void operator()(const G4Step* step, G4SteppingManager* mgr);
+      virtual void operator()(const G4Step* step, G4SteppingManager* mgr)  override;
     };
 
     /// Concrete implementation of the Geant4 stepping action sequence
@@ -117,9 +117,9 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4SteppingActionSequence();
       /// Set or update client context
-      virtual void updateContext(Geant4Context* ctxt);
+      virtual void updateContext(Geant4Context* ctxt)  override;
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Get an action by name
       Geant4SteppingAction* get(const std::string& name) const;
       /// Register stepping action callback. Types Q and T must be polymorph!
diff --git a/DDG4/include/DDG4/Geant4TrackingAction.h b/DDG4/include/DDG4/Geant4TrackingAction.h
index 4d1a7129f980a4e47ddad7478c05196f00057f6f..34637d38414b0dc27230a4cc8e8406c3bf88f6d5 100644
--- a/DDG4/include/DDG4/Geant4TrackingAction.h
+++ b/DDG4/include/DDG4/Geant4TrackingAction.h
@@ -87,13 +87,13 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4SharedTrackingAction();
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Underlying object to be used during the execution of this thread
       virtual void use(Geant4TrackingAction* action);
       /// Begin-of-track callback
-      virtual void begin(const G4Track* track);
+      virtual void begin(const G4Track* track)  override;
       /// End-of-track callback
-      virtual void end(const G4Track* track);
+      virtual void end(const G4Track* track)   override;
     };
 
     /// Concrete implementation of the Geant4 tracking action sequence
@@ -134,9 +134,9 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4TrackingActionSequence();
       /// Set or update client context
-      virtual void updateContext(Geant4Context* ctxt);
+      virtual void updateContext(Geant4Context* ctxt)  override;
       /// Set or update client for the use in a new thread fiber
-      virtual void configureFiber(Geant4Context* thread_context);
+      virtual void configureFiber(Geant4Context* thread_context)  override;
       /// Get an action by name
       Geant4TrackingAction* get(const std::string& name) const;
       /// Register Pre-track action callback before anything else
diff --git a/DDG4/include/DDG4/Geant4TrackingPostAction.h b/DDG4/include/DDG4/Geant4TrackingPostAction.h
index c432868ffef70e1a163e13d1fac3d5e2f798099b..e9ccac73bce74afa6ea22c0350ecb373921d51af 100644
--- a/DDG4/include/DDG4/Geant4TrackingPostAction.h
+++ b/DDG4/include/DDG4/Geant4TrackingPostAction.h
@@ -34,7 +34,8 @@ namespace dd4hep {
       typedef std::vector<std::string> StringV;
       StringV m_requiredProcs;
       StringV m_ignoredProcs;
-      bool m_storeMarkedTracks;
+      bool    m_storeMarkedTracks;
+
     public:
       /// Standard constructor
       Geant4TrackingPostAction(Geant4Context* context, const std::string& name = "");
@@ -45,9 +46,9 @@ namespace dd4hep {
       void saveTrack(const G4Track* track);
 
       /// Begin-of-tracking callback
-      virtual void begin(const G4Track* track);
+      virtual void begin(const G4Track* track)  override;
       /// End-of-tracking callback
-      virtual void end(const G4Track* track);
+      virtual void end(const G4Track* track)  override;
     };
   }    // End namespace sim
 }      // End namespace dd4hep
diff --git a/DDG4/include/DDG4/Geant4TrackingPreAction.h b/DDG4/include/DDG4/Geant4TrackingPreAction.h
index 1b6fb181e2391821816c2b13fc74434b03b4f450..ea2971013c9bf01257daccba190fc3bcee5b51f8 100644
--- a/DDG4/include/DDG4/Geant4TrackingPreAction.h
+++ b/DDG4/include/DDG4/Geant4TrackingPreAction.h
@@ -35,9 +35,9 @@ namespace dd4hep {
       /// Default destructor
       virtual ~Geant4TrackingPreAction();
       /// Begin-of-tracking callback
-      virtual void begin(const G4Track* track);
+      virtual void begin(const G4Track* track)  override;
       /// End-of-tracking callback
-      virtual void end(const G4Track* track);
+      virtual void end(const G4Track* track)  override;
     };
   }    // End namespace sim
 }      // End namespace dd4hep