product.tpl err

[MackStores.Com]

<!--HOOK_PRODUCT_TAB -->
		<section class="page-product-box">
			{$HOOK_PRODUCT_TAB}
			{if isset($HOOK_PRODUCT_TAB_CONTENT) && $HOOK_PRODUCT_TAB_CONTENT}{$HOOK_PRODUCT_TAB_CONTENT}{/if}
		</section>
		<!--end HOOK_PRODUCT_TAB -->

so here is the code of the default theme. now see if I add some review there . fine it shows if approved. now try a module  which adds a something to  $hook_product tab and then $hook_product_tab_content.

 

so basically here

 

what it will do is put two id tabs  together in $hook_product_tab. and then  the first content and then the second content.