diff --git a/FullSimLight/src/MyPrimaryGeneratorMessenger.cc b/FullSimLight/src/MyPrimaryGeneratorMessenger.cc
index 36abb8de2317607133fc7f92e37efb9d69b9303f..345cd35d28b3fded79d3ff8c11ec535908ac3fb6 100644
--- a/FullSimLight/src/MyPrimaryGeneratorMessenger.cc
+++ b/FullSimLight/src/MyPrimaryGeneratorMessenger.cc
@@ -10,7 +10,7 @@
 
 
 MyPrimaryGeneratorMessenger::MyPrimaryGeneratorMessenger(MyPrimaryGeneratorAction *gun) : G4UImessenger(),
- fTheGun(gun), fGunDirectory(nullptr), fPrimaryTypeCmd(nullptr), fPrimaryEnergyCmd(nullptr), fPrimaryDirCmd(nullptr) {
+ fTheGun(gun), fGunDirectory(nullptr), fPrimaryTypeCmd(nullptr), fPrimaryEnergyCmd(nullptr), fPrimaryDirCmd(nullptr), fPrimaryPosCmd(nullptr) {
  fGunDirectory     = new G4UIdirectory("/mygun/");
  fGunDirectory->SetGuidance("gun control");