If this Form is modal, and the user clicked on OK (or accepted it by typing Enter), this calls GoPropertyForm.ModifyObjects to commit any changes selected by the user. If this Form is modeless, this just Hides the Form. (Inherited from Northwoods.Go.Draw.GoPropertyForm)
Determine whether the OK and Cancel buttons are visible, according to whether this Form is modal, and if so, position them appropriately at the bottom right corner of the Form. (Inherited from Northwoods.Go.Draw.GoPropertyForm)