>Hello,
>
>Does anyone know why is that and how this can be explained in OOP paradigm?

See: DataEnvironment Subclass Thread #794205 Message #794205

About all you can do is create a DE for each form, then specify that DE in the Form DEClass/DEClassLibrary properties. You have to modify the DE class in the Class Designer or in a PRG file. You can not modify it in the Form Designer, but you can add Cursor objects and CAs.