Thanks. This is a test I did. I am not sure if I am right or wrong but I guess in the second case the superclass of Item becomes Moose::Object, not Catalyst::Controller::FormBuilder, and that's why Catalyst is complaining about. Am I right?

[1]
use Moose;
BEGIN { extends 'Catalyst::Model::DBIC::Schema' };
print "$_\n", foreach @MyApp::Controller::Item::ISA;
<result>
Catalyst::Controller::FormBuilder
[2]
use Moose;
use base qw/Catalyst::Controller::FormBuilder/;
print "$_\n", foreach @MyApp::Controller::Item::ISA;
<result>
Moose::Object
Catalyst::Controller::FormBuilder
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