Could you explain a little more about what you trying to accomplish? e.g. A ViewStack typically is going to be showing something, and that's the selectedIndex of the LinkBar. If the LinkBar's selectedIndex becomes unset (or set to -1?), what do you expect the ViewStack to show?
Ideally I would want it so that if the selectIndex is unset or set to -1 then the viewstack would display nothing. similary to how setting the selected index of a combobox to -1 would show nothing in the combobox. However setting the selected index of a linkbar to -1 will just select index 0. is there anyway to achieve this operation?
Maybe create linkbar dynamically?