myExtractUnstructuredGrid->ClearRegisteredCells();
myExtractUnstructuredGrid->ClearRegisteredCellsWithType();
myExtractUnstructuredGrid->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::ePassAll);
myExtractUnstructuredGrid->ClearRegisteredCells();
myExtractUnstructuredGrid->ClearRegisteredCellsWithType();
myExtractUnstructuredGrid->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::ePassAll);