Hi again, tamaguchi,

As for mystery #1, you don't want to use pack, you want to use createWindow instead, which is the mechanism by which you can put widgets into a Canvas.

Try this:

#!/usr/bin/perl -w
use Tk;
use strict;
use warnings;
                                                                      
+          
my $mw = MainWindow->new;                                            
my $c = $mw->Scrolled('Canvas',
    -width => 500,
    -height => 500,
    -background =>'blue',
    -scrollregion => [ 0, 0, 1000, 1000 ]
);
                                                                      
+          
$c->pack(-expand => 1, -fill => 'both');
$c->createRectangle(100, 100, 150, 150, -fill => 'yellow');
                                                                      
+          
my $plus = $c->Button(
    -text => '  +  ',
    -command => sub { $c->scale("all", 0, 0, 2, 2) }
);
my $id = $c->createWindow(28, 20, -window => $plus);

MainLoop;
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