yes, it is possible. To do this, please go to Appearance > Menus section, click in right top corner on "Screen options" button, check categories on list and after this you will be able to add categories into menu. But also when you add "Blog" item within Muffin Builder, while you edit item, you have field named "Multiple Categories" so you can add multiple categories.
I forgot to specify one thing. I want to show only a certain "product" category. For now when I select products, it shows me all of them and I cannot seem to select one or the other.
Product's category can be selected also under Appearance > Menus section as we described above. There is checkbox called "Product categories". The same is possible for "Shop slider" item.
Sorry but you probably misunderstood us. You want to use product categories inside posts item? If this is what you try to do, then of course it is completely not possible. Products are products but posts are posts and you can't mix those options.
Comments
yes, it is possible. To do this, please go to Appearance > Menus section, click in right top corner on "Screen options" button, check categories on list and after this you will be able to add categories into menu. But also when you add "Blog" item within Muffin Builder, while you edit item, you have field named "Multiple Categories" so you can add multiple categories.
Thanks!