[vtkusers] vtkPNMReader generates noise?

[Kacper Pluta]

Hi!
When I read PGM P5 file by vtkPNMReader, the output image contained some noise 
in the left down corner of image. But originally image does not contain any 
noise. 

  pgmReader = vtkPNMReader::New();
  pgmReader->SetFileName(OUT_PGM);
  pgmReader->SetFileDimensionality(3);
  pgmReader->SetDataExtent(rawTree->GetExtent());
  pgmReader->Update();

sreenshot: http://wstaw.org/m/2011/12/15/blad.png

Bug or am I doing something wrong?