You can change the size and geometry of an overrideredirected window, but you must do it manually. See below for a drag example.

FWIW, GTK2/GTK3 has a better override than Tk, check out the second example.

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

use Tk;

my $top = MainWindow->new;

$top->geometry('200x200+200+200');

$top->overrideredirect(1);

$top->Label( -text => 'Click and Drag' )->pack(
    -expand => 1,
    -fill   => 'both'
);

$top->Button(
    -text    => 'Exit',
    -command => sub { $top->destroy }
)->pack;

my @deltaxy;

$top->bind( '<1>' => \&getdelta );

$top->bind( '<B1-Motion>' => \&mousemove );

MainLoop;

sub mousemove {
    my ( $width, $height, $x, $y ) = split /[+x]/, $top->geometry;
    $x = $top->pointerx - $deltaxy[0];
    $y = $top->pointery - $deltaxy[1];
    $top->geometry( $width . 'x' . $height . "+$x+$y" );
}

sub getdelta {
    @deltaxy = ( $top->pointerx - $top->x, $top->pointery - $top->y );
}
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Gtk's better approach.

#!/usr/bin/perl
use warnings;
use strict;
use Glib qw/TRUE FALSE/;
use Gtk2::Gdk::Keysyms;
use Gtk2 '-init';

$|++;

my $window = Gtk2::Window->new('toplevel');
$window->set_title('Z');
$window ->signal_connect( 'destroy' => \&delete_event );
$window->set_border_width(10);
$window->set_size_request(300,200);

my $vbox = Gtk2::VBox->new( FALSE, 6 );
$window->add($vbox);
$vbox->set_border_width(2);

my $hbox= Gtk2::HBox->new( FALSE, 6 );
$vbox->pack_end($hbox,FALSE,FALSE,0);
$hbox->set_border_width(2);

my $button = Gtk2::Button->new_from_stock('gtk-quit');
$hbox->pack_end( $button, FALSE, FALSE, 0 );
$button->signal_connect( clicked => \&delete_event );

my $button1 = Gtk2::Button->new('Global Grab');
$hbox->pack_end( $button1, FALSE, FALSE, 0 );
$button1->signal_connect( clicked => sub{
  my $rc;
  $rc = Gtk2::Gdk->pointer_grab($window->window,1,['button-press-mask'
+,'button-release-mask','pointer-motion-mask'],undef,undef,Gtk2->get_c
+urrent_event_time);
  print "$rc\n";
  $rc = Gtk2::Gdk->keyboard_grab($window->window,0,Gtk2->get_current_e
+vent_time);
  print "$rc\n";
} );

$window->set_position('center');

$window->show_all();


$window->signal_connect( 'key_release_event' => \&keyrelease );

$window->signal_connect (event => sub {
   my ($item, $event) = @_;
   warn "event ".$event->type."\n";
#   print chr(07); #beep
   return 0;  #return 1 prevents window from closing 
  # return 0 lets the signal thru
});

Gtk2->main;

#####################################
sub delete_event {
Gtk2->main_quit;
return FALSE;
}  

sub keyrelease {
    my ( $widget, $event ) = @_;
    print $event->keyval,"\n";
    print chr(07); #beep
    if ( $event->keyval == $Gtk2::Gdk::Keysyms{q} ) {
        Gtk2->main_quit;
    }
    else {
        print "key was ", chr( $event->keyval ), "\n";
    }
}
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