There seems to be something wrong with the mx:ViewStack....
I think the code is pretty obvious but what happens is that
when a Tree is inside a ViewStack one cannot always define
programatically it's dataProvider...
This is quite strange and is seriously bothering me since I'm
trying to use this type of interface in a project....
You may be seeing the deferred instantiation issue.
ViewStack, and some of the other navigator/containers, use
deferred instantiation by default. This means the children of a
view, your tree for example, do not exist until the view has been
selected. So you cannot programmatically access such a control
until it has been made visible. The quick fix for this is to set
the ViewStack creationPolicy="all". Be aware that this can have
negative effects on performance for complex apps. Try it anyway.
However, In your example though there is only one view in the
voewstack, so I would have expected its children to be available.
Perhaps you need to use the creationComplete event instead of