[AccessD] Access 2007 Navigation Pane problem

Hello:

I have an Access 2007 database which appears to have a permanently locked
navigation pane.  Issuing the command (per MS documentation) '
Docmd.LockNavigationPane = False' has no effect - in code, in a macro, or in
the immediate window.  This means I can't get into design view for any
forms, queries, etc.  Makes it a little bit hard to modify :(

The db was converted from Access 2003 .mdb format to Access 2007 .accdb;
compiles OK and runs fine.

When I create a db from scratch in Access 2007 it doesn't have this problem.

Any suggestions?

Thanks,
Doug Steele