Thanks for providing the small functional example! You might consider doing some variation of this:

use Tk;
use strict;  
      
my $mw = MainWindow->new;
my $c = $mw->Scrolled('Canvas',
   -width => 200,
   -height => 200,
   -background =>'blue',
   -scrollregion => [ 0, 0, 500, 500 ]
)->pack(qw/-expand 1 -fill both/);

## Bind Both Press and Release events
my $keyHR = {};
$mw->bind('<KeyPress-Up>',      [\&ButtonPress,   "up",    $keyHR]);
$mw->bind('<KeyPress-Down>',    [\&ButtonPress,   "down",  $keyHR]);
$mw->bind('<KeyPress-Right>',   [\&ButtonPress,   "right", $keyHR]);
$mw->bind('<KeyPress-Left>',    [\&ButtonPress,   "left",  $keyHR]);
$mw->bind('<KeyRelease-Up>',    [\&ButtonRelease, "up",    $keyHR]);
$mw->bind('<KeyRelease-Down>',  [\&ButtonRelease, "down",  $keyHR]);
$mw->bind('<KeyRelease-Right>', [\&ButtonRelease, "right", $keyHR]);
$mw->bind('<KeyRelease-Left>',  [\&ButtonRelease, "left",  $keyHR]);

my $rect = 
   $c->createRectangle(100, 100, 150, 150, -fill => 'yellow');      

MainLoop;

sub ButtonRelease {
   my ($w, $dirKey, $keyHR) = @_;
   $keyHR->{$dirKey} = 0;
   Move($keyHR);
}

sub ButtonPress {
   my ($w, $dirKey, $keyHR) = @_;
   $keyHR->{$dirKey} = 1;
   Move($keyHR);
}

sub Move {
   my $keyHR = shift;
   my $speed = 5;

   my $x = 0;
   $x += $speed if $keyHR->{right};
   $x -= $speed if $keyHR->{left};
    
   my $y = 0;
   $y += $speed if $keyHR->{down};
   $y -= $speed if $keyHR->{up};
   $c->move($rect, $x, $y);
}
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