[Holub]

This is your new /skin1/modules/Bestsellers/menu_bestseller.tpl
I've correct some errors like
'thumbnailbs' -> 'thumbnail'
one excess {/if}

{capture name=bestsellers}
<table cellpadding="0" cellspacing="2">
{foreach from=$bestsellers item=bestseller}
<tr>
{if $config.Bestsellers.bestsellers_thumbnails eq "Y"}
 <td width="30">
 <a href="product.php?productid={$bestseller.productid}&amp;cat={$cat}">
{include file="product_thumbnail.tpl" productid=$bestseller.productid  product=$bestseller.product tmbn_url=$bestseller.tmbn_url}</a>
 </td>
{/if}
 <td>
 <b><a href="product.php?productid={$bestseller.productid}&amp;cat={$cat}">{$bestseller.product}</a></b><br />
{$bestseller.descr}<br />
{$lng.lbl_our_price}: {include file="currency.tpl" value=$bestseller.taxed_price}<br />
 </td>
</tr>
{/foreach}
</table>
{/capture}
{include file="dialog.tpl" title=$lng.lbl_bestsellers content=$smarty.capture.bestsellers extra='width="100%"'}

and this is your LAST 20 ROWS of your new /modules/Bestsellers/bestsellers.php. You should find row with 'if ($threshold)' and replace it to end of file with

	if ($threshold)
		$threshold -= 1;
	
	$search_query['where'][] = " $sql_tbl[products_categories].categoryid IN ('".implode("','", $cat_ids)."')";
	unset($result);
}

#
# Search the bestsellers
#
$search_query['where'][] = "$sql_tbl[products].views_stats > '0' AND $sql_tbl[products].sales_stats >= '".$threshold."'";
$search_query['fields'][] = "xcart_products.descr";

$bestsellers = func_search_products($search_query,
	@$user_account["membershipid"],
	"$sql_tbl[products].sales_stats DESC, $sql_tbl[products].views_stats DESC",
	$config["Bestsellers"]["number_of_bestsellers"]
);

$smarty->assign("bestsellers", $bestsellers);

?>

Enjoy!