What is the correct approach to putting validation on a form??

I've made some changes to the "System:Close Opportunity" view and I want to add some form validation before closing the form. I've hidden the OK button and added a new "Save" button that triggers my form validation. The form is opened from "System:Opportunity Detail" with this code: Set objMainView = Application.MainViews.Add("System:Close Opportunity", 0, False) 'DNL ... If objMainView.ShowModal = mrOK Then I tried to close the customized form with both if these options: Application.BasicFunctions.CloseCurrentView(FALSE) ...(read more)