The 'Delete' button will delete what you have highlighted depending on the context.
The Delete Button at the top of the screen on the Ribbon will delete the highest level object. Whilst the delete on a tab will delete the item shown on the tab on that line level.
Example of Both Deletes within Sales:
- Click on 'Sales'
- Click on Orders
- You will see a 'Delete' at the Header and a 'Delete' on the line items of that order.
- Click on One of the Orders
- If you highlight the Sales Order and click on Delete at the top of the screen, it will delete the whole order.
- If you click on Delete on the Line Level of the Sales Order, it will delete the Product/Line that you have highlighted or if you click on Control and highlight each line it will delete the lines highlighed in blue.