When you create the second form, you can pass the parent form as a parameter. Store this parameter in as a property of the child form. Then in the unload() method of the child form, call a method you with to execute in the parent form.

* In the parent form
THIS.ChildForm = CREATEOBJECT('Form2',THIS)



* In the child form's Init(), save the parent form as a property
PROCEDURE Init(loParentForm)
THIS.ParentForm = loParentForm


* In the child form's Unload method()
IF VARTYPE(THIS.ParentForm) = 'O'
THIS.ParentForm.DoSomething()
ENDIF


Note, this will not prevent users from being able to change values on the parent form. You should probably make the child form modal if you want to prevent users from doing anything on the parent form until the child form has been released.

Kurt