if you would be kind enough to put the entire runnable code example into a single code block, i might be able to help you...... at first glance you mix grid and pack...... i don't think it is wise to mix layout managers

....as far as auto-resizing goes, resizing the mainwindow is usually a bad option..... what you should do, is pack your buttons in a Scrolled Pane, and let the scrolled pane adjust the size of the scroll region to accomodate extra buttons......or look at the following

#!/usr/bin/perl
use strict;
use Tk;

my $mw = tkinit;

my %cb;
my $f = $mw->Frame->pack(-anchor => 'w');
foreach (qw/Author Reviewer File Status Mine/) {
    $cb{$_} = $f->Checkbutton(-text => $_)->pack(-anchor => 'w');
}

my $on_off = 1;
foreach (['Enable', 1], ['Disable', 0]) {
    $mw->Radiobutton(
-text     => $_->[0],
-command  => [\&ChangeAuthor, $_->[1]],
-variable => \$on_off,
-value    => $_->[1],
    )->pack(-side => 'left');
}

MainLoop;

sub ChangeAuthor {
    if (shift) {
$cb{Author}->pack(-before => $cb{Reviewer}, -anchor => 'w');
    } else {
$cb{Author}->packForget;
    }
}
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