It would be great if when running multiple products you had the ability to associate multiple solution categories with that individual products. For example you may have one category with foldres and solutions that relate to that individual product itself but also another category that is common to all products thus enabling you to only maintain one instance of the common category solutions for all products whilst still delivering additional solution content relating to the specific product.
Whilst the idea of being able to set the visibility of a folder works well, to effectively achieve sharing common solutions across multiple products with this feature wold require you to place everything within one category only. Ideally setting the visibility on the Category is what is really sought.

