docs: def on_m_save_file(self,event):
  
          '''
          save demag_orient.txt
          (only the columns that appear on the grid frame)
          '''
          fout = open(os.path.join(self.WD, "demag_orient.txt"), 'w')
          STR = "tab\tdemag_orient\n"
          fout.write(STR)
          headers = [header[0] for header in self.headers]
          STR = "\t".join(headers) + "\n"
          fout.write(STR)
          for sample in self.samples_list:
              STR = ""
              for header in headers:
                  sample_index = self.samples_list.index(sample)
                  i = headers.index(header)
                  value = self.grid.GetCellValue(sample_index, i)
                  STR = STR + value + "\t"
              fout.write(STR[:-1] + "\n")
          if event != None:
              dlg1 = wx.MessageDialog(None,caption="Message:", message="data saved in file demag_orient.txt" ,style=wx.OK|wx.ICON_INFORMATION)
              dlg1.ShowModal()
              dlg1.Destroy()