@edvin in the program posted above (listed under 11:30 PM my time), it looks like onDock() isn't called for every opened stage. When the app is opened, the View is displayed and the onDock is called. This is using the normal App(View::class) technique.
In my File > New Window function, I use find<View>().openWindow(). In that case, the onDock isn't called. I think there's a problem in the state tracking and the app thinks additional instances of View are showing already. I haven't tested a Fragment, but I think this is supposed to work with Views that are scoped.
I moved my binding code to onBeforeShow(). The version below works