“Unknown data source ” best practice error on forms

I recently ran into a problem on the RetailPeriodicDiscount form where I was getting a best practice error after adding a new field to the form. I spent a long time trying to work out what was wrong and, after much tearing of hair, realised that the datasource mentioned in the error didn’t exist on the form. Looking at it more closely I could see that the last few characters of the datasource name in the error message were missing. The error that I got was… Unknown data source RetailPeriodicDiscount_RetailDiscountMix...(read more)