Comment 6 for bug 540195

better validate version:
  def validate(self):
    if len(self._data) != 3:
      self.error = ""
      return False
    for key in ["kind", "keytext", "comment"]:
      tmp = self._data.get(key)
      if not tmp or not tmp.strip(): # reject empty or just spaces!
        self.error = key
        return False
    return True