Measure not accepting row / filter context of a give table column

[Dicken]

Hi,
I have a very simplified version of a problem I've had before and need to get to the bottom of what is happening as I think I'm making a very basic error.

I have 3 tables, a measure calculating total sales, if I create a pivot table , if I take the customer from the sales table the measure works, if I take the product form either the product or sales table the measure works, but if I take the customer form the customer table I have a blank row created and I can see why and when the measure is dropped in if filters the table to just the blank.
I've attached the workbook show all 3 examples.

What am I doing wrong and not understanding?

Richard.

[CK76]

In your model. You have [Customer] from Customer table related to [Product] in Sales table. This is causing this behavior.

You need to relate [Customer] to [Customer]
2022-06-01 11_10_00-Power Pivot for Excel - ForumDT.jpg

[Dicken]

Thank you,
I knew I must be doing something pretty stupid. not for the first time. 😕

Richard