Choose the Filter... menu item to run filters
  interactively on a specified file.

  The filters provided by DTM mask data in result files
  that varies from one test run to the next. You can also
  use the filters on files that are not provided by DTM.

  The filter operation enables you to prepare benchmarks
  for association with tests or to see how result files
  would look if filters were run on them.

  Be aware that when you use filters, DTM deletes the
  original unfiltered result file, leaving only the
  filtered file. Using some filters on interactive tests
  that contain escape sequences can cause DTM to delete
  information that is essential to the test.