>>Did you verify that third button is based on the member class ?
>
>I tried that too. He right. Vfp don't run init event more button than implemented in buttongroup class. I think so it's might a bug.
>
>but take care of a point. member classes init event works, option button's init events don't works in form.

This is by ( bad ) design.
Help:

Member Classes (Visual FoxPro)

Note:  
On an .scx form, if you add instantiation code to the member class's Init event, 
Visual FoxPro disregards that code and only the Init code for the member class definition runs.
However, with visual class library (.vcx) forms, Visual FoxPro creates a true subclass.
You can safely add instantiation code for other events such as Click. 

Another scx's problem is on the memberclass object's Name,
- at Init time, the name is not assigned.