Comment 9 for bug 996816

I'm wrote on this bug report because I use mail module.
And when I use it through plugin, plugin_thunderbird module, mail.thread try to retrieve all models (in message_capable_models method) inherit mail.thread with this condition :
-> if 'mail.thread' in getattr(model, '_inherit', []):

But It doesn't get all models just models...
Depend of instance order...