Hi,
I haven't noticed that, apparently this is a new thing with Virtuemart core.
As i have said, the background of Fancy Product Slider Module is as same as the official "VM - Product Module". I am 99.9% sure, the same thing will happen with VM Product Module as well.
Deciding what products to list or what product to hide is taken care by the Virtuemart component core files.
Our module just use the global function of
$productModel = VmModel::getModel('Product');
and calling this function (which is defined by this Virtuemart core file:
/administrator/components/com_virtuemart/models/product.php
public function getProductListing ($group = FALSE, $nbrReturnProducts = FALSE, $withCalc = TRUE, $onlyPublished = TRUE, $single = FALSE, $filterCategory = TRUE, $category_id = 0) {
to gather the products.
In my opinion, it is a cool and useful feature to use manufacturer filtering, but you don't like and want to disable, fair enough. But it would require some Virtuemart core hacks, which is not recommended and beyond our free support. Indeed, touching any core Virtuemart files will eventually cause you some bigger problem in the future.
Regards,
support