message: avoid calling TClonesArray::Compress()
diff: @@ -77,7 +77,7 @@ Int_t AliAnalysisTaskDiffCrossSections::PseudoTracks::RemoveTracks(UInt_t mask)
  }
  }
  if (nRemoved) {
  - fTracks.Compress();
  + // avoid calling TClonesArray::Compress() which is expensive
  fTracks.Sort();
  }
  return nRemoved;
  