Grouping gives different results everytime I refresh report (1 Viewer)

[wan2fly99]

I have created a report that groups customer names within territory.

Each customer belongs to a territory. Each customer has many invoices
which I want to list


So I select customers based on a Territory they belong to. I use a
Prompt paramater
to select which Territory I want to report on


I then group the data by Customer-No.


Sometimes I will get the data okay, invoices under proper customer.


When I prompt again for new data, all a sudden the result is not
grouped correctly.


I delete the group and re-insert the group. Refresh report and it
appears correct again.


Cannot understand what is going on


Any help is apapreciated