We have added the product attributes filter to the product listing of the manufacturers. Now, not only could the store owner enable or disable the product attributes filter but also could link the products attributes filter to the manufacturers/category filter under admin panel -> Configuration -> Configuration -> Product Listing Sort Order as follows:
Once the store owner set 'link the products attributes filter to the manufacturers/category filter' as true, the customer could filter the products with products attributes filter and manufacturers/category filter. For example, if there are following attributes in the products listing:
Color - Black ,Red
The customer could filter the products with the category or manufacturers filter box firstly and then you could filter the search results with the product attributes filter.
We will compress a package for this feature and post it here soon. This feature will be available in v1.1.8.
Thanks for your report.