Suppliers shouldn't be able to enter negative values via credit memos when invoicing in BN

[mehmet89]

Is there a way to prevent suppliers from entering negative values ​​when creating a credit memo or correcting an invoice?

[Jeremy_Deo]

I'm only specialized on the FI side and ECC/S4 hana cloud public version for this topic but I've done some researches on the web and found something talking about "Custom Validation Rules".

Is it something you have heard of ?