Default for "Level of rollback on errors"

Hi,

I have one question about DSN setting dialog.
Following phenomenon have confirmed in 09.05.0200, 09.05.0210, 09.03.0300 version.

After create a DSN by ODBC Datasource Administrator,
Setting of "Level of rollback on errors" in "Advanced Options (DataSource)"(Page 2)
is in not checked state.
In this state it work as "Statement" setting, it mean that queries in BEGIN block
will be surrounded with SAVEPOINT statement before executed.

But when "Level of rollback on errors" setting is in not checked state,
if I press "OK" button (in "Advanced Options (DataSource)"(Page 2) dialog)
and reconfirm "Level of rollback on errors". The setting become "Transaction"
 (rollback the whole transaction).

So, is it intentionally sir?

I wonder if what is exactly the default for this setting.

Thanks and best regards,
Dang Minh Huong
NEC Solution Innovators, Ltd.
http://www.nec-solutioninnovators.co.jp/en/