- For convenience, create a Minium site
- Go to Control Panel -> Commerce -> Discounts
- Create a new discount
- Set target as "Apply to Product"
- Proceed creating a valid discount
- Go to the Products tab
- Click the plus button
- Select a product(e.g. ABS Sensor)
- Click Add
- Click again the plus button
- Change the number of visible entries
Already selected products should not be selectable anymore.
After having changed the number of visible entries every single product is selectable, even the products already selected.