When one uses the simple navigation on the left, which is often asked for by
customers, then using an URL to an external Link does not take over the target,
that is selected in the options-tab.

This is easily changed if the following piece of code ist changed from this:

{else}
<li><a href="{$node->url}"><span>{$node->menutext}</span></a>

to this

{else}
<li><a href="{$node->url}" {if $node->target}target="{$node->target}" {/if}
><span>{$node->menutext}</span></a>

Since setting the target is very basic HTML I think it should be in there.

Kind regards,
Jan van Leeuwen