There are a couple of ways, one is to use the raisecmd callback, to set the current page. This will make a callback for the current page, with a right-click release.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::NoteBook;

my $current = 0;

my $mw=MainWindow->new(-title=>'Notebook tab colors demo');

my $XIMG = <<'EOF';
/* XPM */
static char * x_xpm[] = {
"12 12 3 1",
"     c None",
".    c #FF6060",
"+    c #8F6060",
"  .     .   ",
" .+.   .+.  ",
".+++. .+++. ",
"+.+++.+++.+ ",
" +.+++++.+  ",
"  +.+++.+   ",
"  .+++++.   ",
" .+++.+++.  ",
".+++.+.+++. ",
"+.+.+ +.+.+ ",
" +.+   +.+  ",
"  +     +   "};
EOF

my $RED = $mw->Pixmap(-data => $XIMG );

my $BXIMG = $XIMG;
$BXIMG =~ s/#FF6060/#6060FF/;
$BXIMG =~ s/#8F6060/#60608F/;
my $BLUE = $mw->Pixmap(-data => $BXIMG );

my $GXIMG = $XIMG;
$GXIMG =~ s/#FF6060/#60FF60/;
$GXIMG =~ s/#8F6060/#60FF60/;
my $GREEN = $mw->Pixmap(-data => $GXIMG );

my $nb = $mw->NoteBook(
          -background=> 'white',
          -inactivebackground => 'black', 
           )->pack();

$nb->bind('<ButtonRelease-3>', sub{
                   print "$current is being saved\n";
                 });

my @colors = ($RED,$BLUE,$GREEN);

for my $tab (qw/page1 page2 page3 page4 page5 page6/){

     my $frame = $nb->add($tab, 
              -raisecmd => sub{ print "@_\n"; 
                                print $tab,"\n";
                                $current = $tab;
                                print "$current is current\n";
                                }, 
              -image=> $colors[0], );

     $frame->Label(-text => $tab)->pack;
     $frame->Label(-text => 'a Label in '.$tab)->pack;
     
     push (@colors,shift(@colors)); #shift colors around

}

MainLoop;
[download]