The custom region doesn't quite work yet, so just expose the underling
bar so we can still get the shared behavior. Maybe the region will get
fixed later on.
JavaFX & ScalaFX already have one of these, but this handles padding
and automatically set up the apply, ok, cancel trilogy (though you can
disable any of these).
This ensures there will be at most one copy of the stage, which will be
created and destroyed as needed. Trying to create a second just brings
the first into focus. This is good for things like preferences windows.
This makes it really convenient to take a data structure like a
`ObservableBuffer`, which normally has special operations to watch for
different CRUD operations on its individual members, and treat the whole
thing as a solid value. This lets you turn it into an `ObservableValue`
where you get a notice of changes and then you can use the normal
operations like `map` and `flatMap` to react to changes.
Because this requires reprocessing the entirety of the contained values,
this may not perform as well as if you subscribe to more granular update
messages.
It is possible to round-trip these collections back to the ScalaFX
native collections using the other utilities available. This will be
required if you want to use the output to back something like a table.
Sarah Gerweck