View:Filter: private: array
  This is object defined filter information. this instavar variable is
  composed of theree paralel arrays:
  first of them consists of filter names as menu items (character)
  second of them consists of the filter expression (Character)
  third is the array of logical values defining if the user is enabled
        to modify the filter definition. The filter definitions created
        in a program are unchangeable but there is a possiblity to change
        the user run time defined filters.