procedure MainForm.SaveAttachment;
var
  lAlwaysUnzip: Boolean;
begin
  if not GuiOptions.AlwaysUnzipAttachments then
  begin
    if VerifyMessage('Do you want to unzip the saved attachment?' tdiConfirmation, [cbYes, cbNo], 0,
      mtInstruction,  'Always unzip attachments', lAlwaysUnzip) = mrOK then
    begin
      GuiOptions.AlwaysUnzipAttachments := lAlwaysUnzip;
      // unzip attachment
    end;
  end;
end;