If I understand you right, all you want to do is to make the columns larger, right? Update: Are you looking to make the columns wider, or the buttons at the top taller (in which case I don't get it...they are just a bit larger than the text, which at least on Win32 is just like every other application)?

...
$mw->minsize(700,400);
...
my $c1 = $scrolledMListbox->columnInsert('end',  -text => 'Path');
$c1->configure(-width => 25);
my $c2 = $scrolledMListbox->columnInsert('end', -text => 'Modified');
$c2->configure(-width => 25);

my $c3 = $scrolledMListbox->columnInsert('end',  -text => 'Dir');
$c3->configure(-width => 25);
my $c4 = $scrolledMListbox->columnInsert('end',  -text => 'File');
$c4->configure(-width => 25);
[download]

I am not certain whether you were thinking to modify the actual module just as an example or what, but normally you want to stay OUT of module code until you have exhausted other possibilities. Have you tried not hacking the module?