I added

use warnings;
use strict;
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and made a few fixes for that, and your script works with the mousewheel here. What problem do you see?

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

my $mw = new MainWindow;
my $main = $mw -> Scrolled("Canvas",-scrollbars=>'e')-> pack(-side => 
+'left', -fill => 'both', -expand => 1);

my $canvas = $main->Subwidget("canvas");

Tk::bind($canvas, '<MouseWheel>', [ sub {$canvas->yview('scroll',-($_[
+1] / 120) * 3,'units')}, Ev('D')]); 

my $see = "\nHaaa, See that and die!";

my $info = $main->createText(180, 15, -text => "$see", -font => 'Arial
+ 11 bold' , -fill => 'red');
$main->configure(-scrollregion => [0,0,2000 , 2000]);

my $canvas_cube = $main->Canvas(-width => 15, -height => 15, -backgrou
+nd => 'green');

$main ->createWindow(75,75, -window => $canvas_cube);

$canvas->focus;

MainLoop;
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