Try adding a break tag to the bottom div, like this
Code:
{*
$Id: dialog.tpl,v 1.8 2008/11/26 06:31:47 cray Exp $
vim: set ts=2 sw=2 sts=2 et:
*}
{* Mods - replaced entire contents to make rounded boxes *}
{if $printable ne ''}
{include file="dialog_printable.tpl"}
{else}
<div class="xrounded{if $additional_class} {$additional_class}{/if}">
<b class="xtop">
<b class="xb1"></b>
<b class="xb2 color_a"></b>
<b class="xb3 color_a"></b>
<b class="xb4 color_a"></b>
</b>
<div class="xboxcontent{if $additional_class} {$additional_class}{/if}">
<h1 class="color_a{if $printable ne 'Y'} title-with-sort-row{/if}">{$title}</h1>
<div class="dialog-search-sort-bar">
{if $selected eq '' && $direction eq ''}
{include file="customer/search_sort_by.tpl" selected=$search_prefilled.sort_field direction=$search_prefilled.sort_direction url=$products_sort_url}
{else}
{include file="customer/search_sort_by.tpl" url=$products_sort_url}
{/if}
</div>
<div class="content{if $additional_class} {$additional_class}{/if}">{$content}<br /></div>
</div>
<b class="xbottom">
<b class="xb4"></b>
<b class="xb3"></b>
<b class="xb2"></b>
<b class="xb1"></b>
</b>
</div>
{/if}