"... wonder if I could add the 'scroll' feature ..."

Tk::Scrolled explains how to do that.

It sounds like your application is very similar (at least in terms of GUI layout) to one I wrote quite a few years ago and which I run (without any problems) fairly regularly. I put the entire Tk::NoteBook in a scrolled Tk::Pane.

Here's a severely cutdown version of just the relevant code:

my $mw = MainWindow->new();
...
build_main_pane(\$mw);
...
sub build_main_pane {
    my $mw = ${+shift};

    my $mp = $mw->Scrolled(q{Pane},
        -scrollbars => q{osoe},
        -sticky => q{nsew},
    );

    $mp->pack(-fill => q{both}, -expand => 1);

    build_notebook($mp);

    return;
}

sub build_notebook {
    my ($parent) = @_;

    my $nb = $parent->NoteBook();

    $nb->pack(-fill => q{both}, -expand => 1);

    build_pages($nb);

    return;
}

sub build_pages {
    my ($nb) = @_;

    build_example_page($nb);
    build_other_page($nb);
    ...
    build_last_page($nb);

    return;
}

sub build_example_page {
    my ($nb) = @_;

    my $example_page = $nb->add(example_page =>
        -label => 'Example Page',
        ...
    );

    ...
}
[download]

Thanks a bunch Ken. This piece of code really help. I know what I should do now. I'm applying your sample code in my script. Big thanks! :)

Tips Re: Tk::Notebook - Scrolling Tabs (diy)

Example

#!/usr/bin/perl --
use strict;
use warnings;
use Tk;
Main( @ARGV );
exit( 0 );
sub Main {
    my $mw = tkinit();
    my $nb = $mw->NoteBook( -backpagecolor => 'red',)->pack(qw/-expand
+ 1 -fill both /);
    Colors($nb);
    $mw->geometry("200x200+200+200");
##    $mw->WidgetDump;
    $mw->MainLoop;
}
sub Colors {
    my( $nb ) = @_;
    my @color = qw[ pink maroon green OliveDrab4 PaleVioletRed3 RosyBr
+own2 PeachPuff4 WhiteSmoke azure3 chartreuse1 coral3 gold1 firebrick4
+ linen salmon4 tomato2 ];
    for my $red( @color ){
        my $frame = $nb->add( $red, -label => $red, );
        my $emraf = $frame->Scrolled('Pane', -background => $red)->pac
+k(qw/ -expand 1 -fill both /);
        $emraf->Button( -text => $_, )->pack( -side => (qw/ left right
+ top bottom/)[rand 4] ) for @color;
    }
}
[download]

Thank you Anonymous Monk, your sample codes helps me to understand on the concept. Appreciate!