Adding, then removing, and then adding a JFXPanel to the same component in the Swing scene graph leads to a NullPointerException in GlassScene because the sceneState is null. Removing JFXPanel calls JFXPanel.removeNotify which calls Window.hide which calls SceneHelper.disposePeer -> Scene.disposePeer -> EmbeddedScene.dispose -> GlassScene.dispose which sets "sceneState" to null... so when GlassScene.updateSceneState is called, it results in NPE. Fix is to check if `host` (which is usually javafx.embed.swing.JFXPanel$HostContainer for active JFXPanel) has been reset/deleted which is done when `EmbeddedScene.dispose` is called during removeNotify and abstain from updating the scene state
------------- Commit messages: - 8334593: Adding, removing and then adding a JFXPanel again leads to NullPointerException Changes: https://git.openjdk.org/jfx/pull/1493/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1493&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8334593 Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jfx/pull/1493.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1493/head:pull/1493 PR: https://git.openjdk.org/jfx/pull/1493
