From In-Portal User Manual

Items

On this tab, you can specify what the discount applies to – specific products, or the entire order. Below are the descriptions of the toolbar action icons on this tab:

• New product – adds one or more products to the discount list. If you select a category, all products in that category and all of its subcategories will be added. Note, that the category itself is not added. This means, that if you create a new product in that category in the future, it will not be a part of this discount. This feature also allows you to quickly add some, but not all products in a category – you can add its entire contents, and then remove those products that you do not want to discount.
• Delete – removes items from the discount.
• Entire order – specifies, that the discount is for an entire order, and not for specific products. If you press this button after you have added one or more products, you will be prompted to remove them automatically. A discount cannot be for an entire order and some products at the same time.