#!/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 );
}
[download]

Or, you can temporarily turn off overrideredirect, resize, and then turn it back on. But while it is turned off, it will only be visible on the current desktop. So you will have to work out some scheme to turn off, resize, and immediately turn it back on again. Here is just a simple "turn off".

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

my $mw = tkinit;
$mw->geometry("200x300+200+200");

$mw->overrideredirect(1);   # set the override-redirect flag 

$mw->Button(
   -text       => 'Quit',
   -command    => sub { Tk::exit(0) },
)->pack( -side       => 'bottom',);

$mw->Button(
   -text       => 'Restore WM Controls',
   -command    => \&restore_WM,
)->pack( -side       => 'bottom',);

MainLoop;

sub restore_WM{
 $mw->withdraw;
 $mw->overrideredirect(0);   # set the override-redirect flag 
 $mw->update;
 $mw->deiconify;
}
[download]