view stack not populating its children while changing views by using togglebuttonbar

Question

I am having a view stack I had this as a data provider to toggleButtonBar.

When I run my application I can see only the view stacks Default view (Zero).

If I try to change the view by clicking toggleButtonBar, the sceen will be empty.

If I change the viewStack.selectedIndex = 1; then I can see index one's screen again; if I try to see index zero's screen, the screen will be empty.

I am trying to analyze this issue but am not able to do so. Help me out.

Thank you.