Access DSUM in access 2003 refresh problem

[fbnewtz]

I successfully have a control source on a form calculatiing the values in a subform. However when I change the record in the subform it does not update the textbox in the form unless I exit the form and return on a different record.

How can I update this value when the record changes in the subform? I have tried refreshing different objects in each form. I have created a function that sets the dsum to a variable and then set the control source to the function name, but that is not calculating properly.

Any ideas?

Thanks,

Fred