Sales Order should not be saved with no items

Is there a possibility to keep users from saving a sales order with no items.

Sometimes when creating a standard order and after entering
the Sold-to party
the PO Number
and the Req. deliv.date
our users accidentally save the order without entering any items, thinking they already completed the order. (For example when they needto answer a call in the meantime)

Is there a customizing setting to not save the order when there are no items in it? Or to display an error message?

Thanks in advance

Jakob