message: make sure all sub-events are preread in BeginEvent
diff: @@ -540,8 +540,6 @@ AliVParticle* AliMCEvent::GetTrack(Int_t i) const
  Int_t ntref = 0;
  TObjArray *rarray = 0;
  -
  -
  // Out of range check
  if (i < 0 || i >= fNparticles) {
  AliWarning(Form("AliMCEvent::GetEntry: Index out of range"));
  @@ -825,6 +823,16 @@ void AliMCEvent::InitEvent()
  void AliMCEvent::PreReadAll()
  {
  // Preread the MC information
  + if (fSubsidiaryEvents) { // prereading should be done only once all sub events read and initialized
  + TIter next(fSubsidiaryEvents);
  + AliMCEvent* evt;
  + while((evt = (AliMCEvent*)next())) {
  + evt->PreReadAll();
  + }
  + return;
  + }
  +
  +
  Int_t i;
  // secondaries
  for (i = fStack->GetNprimary(); i < fStack->GetNtrack(); i++)
  