Another option is to use the 'form' geometry manager:

#!/usr/bin/perl
use strict;
use warnings;
use Tk;
use Tk::widgets qw(LabFrame);

my $mw = MainWindow->new;
$mw->title('First App');

#--- Locations

my $locations_f = $mw->LabFrame(
    -label      => 'Locations',
    -labelside  => 'acrosstop',
    -foreground => 'blue',
);
$locations_f->pack(
    -side   => 'top',
    -expand => 1,
    -fill   => 'x',
);

#-- locations

my $llocations = $locations_f->Label( -text => 'Locations' );
$llocations->form(
    -top  => [ %0, 0 ],
    -left => [ %0, 5 ],
);
my $elocations = $locations_f->Entry(
    -width => 20,
);
$elocations->form(
    -top      => [ %0, 0 ],
    -left     => [ %0, 80 ],
    -padright => 5,
);

#-- types

my $ltypes = $locations_f->Label( -text => 'Types' );
$ltypes->form(
    -top  => [ $llocations, 8 ],
    -left => [ %0, 5 ],
);

my $etypes = $locations_f->Entry(
    -width => 15,
);
$etypes->form(
    -top       => [ '&', $ltypes, 0 ],
    -left      => [ %0,  80 ],
    -padbottom => 5,
);

MainLoop;
[download]

Regards, Ştefan