[web2py] Differing Form Presentation with SQLFORM readonly=True

[Art Zemon]

Hello,

I have a field defined like this:
   Field('state', 'string', requires=IS_IN_DB(db, 'state.id',
   'state.abbreviation', zero=T('Choose one')))

If I create a SQLFORM like this,

   form = SQLFORM(db.address, address)

I get what I expect: a drop-down menu displaying all of the 
state.abbreviation values. But if I generate the form like this,

   form = SQLFORM(db.address, address, readonly=True)

I see state.id and not state.abbreviation. Is this expected behavior or 
a bug? I am running Version 1.91.6 (2011-01-03 17:55:14)

    -- Art Z.