Application error with Non-ascii contact title shortcut

Binary package hint: openerp-server

Application error with Non-ascii contact title shortcut

I operate as below and application error happend:
1) In menu "Partners->Configuration->Titles->Contact Titles"
I created a new title with shortcut in Non-ascii code,for example "先生"

2) In menu "Partners->Partners->New Partner"
I created a new partner with contact title as that created in step 1).

3) If save partner,Application error below displays on UI:
"unicode() argument 2 must be string, not None"
and with error log:
"exception:u'warning -- ValidateError\n\nThe value "\u5c0f\u59d0" for the field "title" is not in the selection'"

Can you tell me why and how to fix that?