pl sql allround not show vietnamese utf8 unicode

Question

I use pl sql allround 11 and more info: https://www.allroundautomations.com/plsqldev.html

I try execute command:

select 'Mật khẩu cũ không đúng' from dual;

The editor pl sql allround 11 grid was shown:

M���t kh���u c�� kh��ng ����ng

Correct Toad editor was shown:

Mật khẩu cũ không đúng 

and I compile procedure and function return nvarchar2, same result!!!

please help me configure editor!

Thanks for any suggestion

Answer 1

I have a correct answer!

After compare session connection info toad and plsql allround 11 by command:

/* Formatted on 12/24/2016 12:36:03 PM (QP5 v5.287) */
SELECT *
  FROM V$SESSION_CONNECT_INFO
 WHERE sid = 9

, I see client_charset on plsql is "US7ASCII", Toad is "UTF16"

because I using client oci library that not set NSL_LANG correct to AMERICAN_AMERICA.AL32UTF8.