sub minimize {
    ($state eq 'min') and return;
    $state = 'min';
    $frm3->packForget;

    # Restore "minimal" dimensions, even if user resized GUI
    # References:
	#     http://perlmonks.com/?node_id=942166
	#     http://perlmonks.com/?node_id=957608 
    $mw->geometry(undef);
    $mw->update;
}