Sales Orders Item Checkmarks provide you with a better way to keep track of your inventory.
When adding parts to a Sales Order, if the part is not in Stock, you'll see that the info box in the SO is grayed and the Link circle is empty.
If the part is in Stock, the info box will appear in color blue. You'll be able to click on the box, and a new window will open, which will allow you to browse through the entries you have in Stock. Then, you just have to select the part that you want to sell.
Lastly, when a part is linked, the circle will show you a check mark.
