It still prints the message when I press ? inside the entry. The following works for me, though:
#!/usr/bin/perl
use warnings;
use strict;
use Tk;
my $mw = MainWindow->new->geometry("100x100+799+336");
my $entry = $mw->Entry( -text => '',
-width => 20
)->pack();
$entry->bind('<KeyRelease-question>' => sub { Tk->break });
$mw->bind( '<KeyRelease-question>' => sub { print "? was pressed!\n"
+ });
$mw->Entry->pack;
MainLoop();
($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,