Nadya,
This is one reason why PageFrame, Grid and OptionGroup subclasses should always be defined with 0 contained elements. Then when you drop an instance on a form/in a class you can freely set the number of elements and name them as you please.
>I have option group class, which currently has 2 options with the first being set to 1. In the form I have several instances of this class, where the number of options is set in design time. In run-time I set another option to be 1 (not the first 1). As a result I have 2 options selected: the first one and another one. Is it a bug? Is the only workaround to set first option to 0 prior to setting another option to 1?