WPF Expander is not identifying if it's place inside WPF group Item control

Hi,

We are using WPF Desktop Application, WPF Expander is not identifying if the control is placed inside WPF Group Item control.

And alsoWPF Group Item control is not listing inside Object Mapping WPF controls which is comming under standard windows control.So not able to access buttons inside WPF Expander control. Please provide solution to proceed.

Thanks