Assuming this is using Tk, you need to set pack propagate on for the Scrolled container. See below.

use warnings;
use strict;
use Tk;

my $page = MainWindow->new;
$page->geometry('600x200');

# Create a frame ...
my $suite_fr = $page->Frame->pack(-expand => 1, -fill => 'both');

# Add a label to the frame
$suite_fr->Label(-text => 'Suite:')->pack(-side => 'left');

# create a Scrolled Listbox
my $suite_lb = $suite_fr->Scrolled( 'Listbox',
    -exportselection  => '0',
    -height           => '7',            
    -scrollbars       => 'e',
    -selectbackground => 'gray80',
    -selectforeground => 'black',
    -selectmode       => 'extended'
)->pack(-side => 'left');

my $button = $page->Button(
    -text => '  Fill  ',
    -command => sub{ fillbox($suite_lb) },
)->pack;

MainLoop;

sub fillbox{
    my $self = shift;
    $self->packPropagate(1);

    my @list = 'X' x rand 80;

    # Populate the ListBox with the valid suites
    $self->insert(0, @list);

    $self->Subwidget("listbox")->configure(-width => 0);
}

[download]

In reply to Re: Problem setting width on Scrolled Listbox by thundergnat
in thread Problem setting width on Scrolled Listbox by pirishmonk

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