On both beta versions, NavigationViews don't like being presented in a panel (closing the panel == crash)
v=ui.View(bg_color='red')
n=ui.NavigationView(v)
n.present('panel')
n.close() # or, closing manually
As an aside, the docs don't seem to document the NavigationView constructor.
just curious, why cant you add it as a subview and present the mainview?
Of course, one could, but this is an undocumented limitation/bug -- if NV's in panels crash the app, that should not be allowed.
I don't really like or use navigationview normally, but In this specific case, I was trying to see if presenting a NavigationView as a panel allowed the pushed views buttonitems to show up in the main tabbar, as an easy way of changing context (they don't).