We rent out products with serial numbers.  The problem i have is that even when a rental product is out, that product serial number still shows as available in the dropdown list in the rental order.  I didn't change any setting in the locations but now i've been testing with making the rental location as a non-stock location. that doesn't work either.  Been looking for documentation but i only see the how to set it up and use it part, which is always the case, but not a how to configure doc.  Can someone point me to the right direction please?

thanks!