my $sf_makefiles = $canvas3->Scrolled(qw/Canvas -relief 
flat -width 190 -height 110 -scrollbars e/)->pack(-expand  
=> 1,-fill => 'both');

foreach $file (sort @makefiles) {
  $sf_makefiles->Checkbutton(-text => $file)->pack(-side => 'top',
 -anchor => 'nw');
}