my $button1 = $mw->Checkbutton(
    -variable =>\$config{SavePwd},
    -text => 'Passwort speichern'
)->pack;

my $button2 = $mw->Checkbutton(
    -variable =>\$config{Mode},
    -text => 'Passwort speichern',
)->pack;

$button2->configure(-state => 'disabled');