Richard,

please share screen shot of Customer, Order and Order Details tables in Design view

what happens when you add a new order detail line?

The discount stays at 0%

Create ANOTHER new record and see what it shows.

A default value is set BEFORE a new record is created.  If the default value changes, you have to make another new record in order to get the new default value.

I have tried that the discount rate stays at Zero no matter what unless I change it manually.

In the After Update event of the DiscountRate on OrderF Requery the Subform
    OrderDetailF.Requery

Also try the On Current event.

Do you have any other code that could be preventing the field getting the Default Value?

Here is an example of what can happen, and why a default value is not the best way to do this kind of thing:

Suppose your customer form has 2%, your OrderF shows 2%, so your subform should also show 2%.  That's according to how you set up default values.

If you navigate to different customer that has 4%, your order main form and subform will STILL show 2%.  Navigate to customer with 10%, you will still get 2% on the order forms.  You can do this *forever* and your order forms will show the old default value 2%.

That's because default values are *static*.  It is only calculated *once*: when a *new blank row* is created.

The only way to get rid of 2% is to enter and save the record in the order forms, so Access will create a *new blank record* on the form.  Then and only then will a new default value be calculated based on the current customer.  This is not helpful, because you can't just enter a new record every time you need a new discount.

This is why default values are not good for this purpose.  They are static, and they don't update themselves every second, after every change you make to the customer form.  The only way to get the value at the moment you need, is to calculate it at the moment you need to -- not when you change customer, but when you are actually about to enter a new record on the order subform or mainform.  This is what the BeforeInsert event can do.

I thank you for your help Kevin Robertson, but that does not seem to work either. As far as what you have said Kevin Yip can you tell me where and what to put in the code in before insert event?

When I open the subform by itself without the parent form I get a #Name? error in the discount field does this mean anything?

I just got it fixed. I deleted the subform and started over now it works. Thanks to all.