> Perhaps the header bar should be a part of a new top-level container? This would then be the first and only top-level container of JavaFX. What would happen if you tried to add it to another container?
It would also make it harder to create certain UIs. Right now it is pretty easy to place content below, above, or across the HeaderBar (just layer it in a StackPane), but with HeaderBar being a "top-level" container, this doesn't work. > We may or may not need EXTENDED, if for example, the stage can examine > whether the scene contains that particular type of container and drops the > native title bar, or something like that? (Do we really support setting a > different Scene to an existing Stage?) Well, applications can change Scenes, so we need to account for that. While it would be nice if we could detect whether a HeaderBar is used, and then automatically support that in the native toolkit, we run into the problem of initialization order: We need to know at Stage creation time whether the native toolkit should support custom header bars, but at Stage creation time we might not now whether the scene graph will contain a HeaderBar at all. The only way I can see this work is if we have something like Stage.initHeaderBar(), with the downside of inventing a second and independent scene graph that doesn't interact with the main scene graph. That would be sad, because the single scene graph is one of the biggest features of JavaFX.
