Text field in a form is not updatable after commit

Hi,

I have created a form and put few validation. If you see the attached screen shot, I have marked three fields. The validation is put on the field bank account number.

The currency field (non-updateable) is populated based on the data selected in the field bank accuont number and the field sepa batch is populated based on the currency code.

Another validation is if the currency code is other than EUR, the sepa batch field will be set to value N and the field will not be updatable. But if the currency is EUR, the value will be set to Y and user can update the field.