Andre, In fact this code is almost identical, to what have been there before:
```
{if $hide_left_menu}
{include uri='design:page_mainarea.tpl'}
{else}
<div id="maincontent">
...
{include uri='design:page_mainarea.tpl'}
...
</div>
{/if}
```
I just wanted to exclude smaller part of markup in case of absent left panel. But looks like another approach is needed anyway.