tksleep($mw, 100);

sub tksleep { 
  # Like sleep, but actually allows the display to be 
  # updated, and takes milliseconds instead of seconds. 
   my $mw = shift; 
   my $ms = shift; 
   my $flag = 0; 
 
   $mw->after($ms, sub { $flag++ }); 
   $mw->waitVariable(\$flag); 
}