accepted upstream. to be removed in the next minor release.

https://bugs.gentoo.org/show_bug.cgi?id=496678
http://bugzilla-geant4.kek.jp/show_bug.cgi?id=1537

diff -Naur geant4.10.00/source/geometry/navigation/include/G4TransportationManager.hh geant4.10.00-mod/source/geometry/navigation/include/G4TransportationManager.hh
--- geant4.10.00/source/geometry/navigation/include/G4TransportationManager.hh	2013-12-05 10:28:54.000000000 +0100
+++ geant4.10.00-mod/source/geometry/navigation/include/G4TransportationManager.hh	2013-12-12 01:40:12.341428809 +0100
@@ -68,7 +68,7 @@
        // Accessors for field handling
 
      inline G4Navigator* GetNavigatorForTracking() const;
-     inline void SetNavigatorForTracking( G4Navigator* newNavigator );
+     void SetNavigatorForTracking( G4Navigator* newNavigator );
        // Accessors for the navigator for tracking
 
      inline void SetWorldForTracking(G4VPhysicalVolume* theWorld);
diff -Naur geant4.10.00/source/geometry/navigation/include/G4TransportationManager.icc geant4.10.00-mod/source/geometry/navigation/include/G4TransportationManager.icc
--- geant4.10.00/source/geometry/navigation/include/G4TransportationManager.icc	2013-12-05 10:28:54.000000000 +0100
+++ geant4.10.00-mod/source/geometry/navigation/include/G4TransportationManager.icc	2013-12-12 01:40:12.341428809 +0100
@@ -59,6 +59,7 @@
    fNavigators[0]->SetWorldVolume(theWorld);
 }
 
+/*
 // ----------------------------------------------------------------------------
 // SetNavigatorForTracking()
 //
@@ -70,6 +71,7 @@
 {
    fNavigators[0] = newNavigator;
 }
+*/
 
 // ----------------------------------------------------------------------------
 // GetPropagatorInField()
diff -Naur geant4.10.00/source/geometry/navigation/src/G4TransportationManager.cc geant4.10.00-mod/source/geometry/navigation/src/G4TransportationManager.cc
--- geant4.10.00/source/geometry/navigation/src/G4TransportationManager.cc	2013-12-05 10:28:56.000000000 +0100
+++ geant4.10.00-mod/source/geometry/navigation/src/G4TransportationManager.cc	2013-12-12 01:40:12.345428679 +0100
@@ -124,6 +124,20 @@
    }
 }
 
+
+// ----------------------------------------------------------------------------
+// SetNavigatorForTracking()
+//
+// Set the active navigator for tracking, always
+// the first in the collection of registered navigators.
+//
+void G4TransportationManager::SetNavigatorForTracking(G4Navigator* newNavigator)
+{
+   fNavigators[0] = newNavigator;
+   fActiveNavigators[0] = newNavigator;
+   fPropagatorInField->SetNavigatorForPropagating(newNavigator);
+}
+
 // ----------------------------------------------------------------------------
 // ClearNavigators()
 //