I'm exploring the new prefab workflows in 2018.3 and the editor tools we have at our disposal. I want to know if it is possible to detect when the user is exiting the prefab edit mode in the editor. So far I tried: EditorSceneManager.sceneClosing: https://docs.unity3d.com/ScriptReference/SceneManagement.EditorSceneManager-sceneClosing.html But it seems like the prefab scene does not count as an actual scene and so the event is never called when exiting the prefab edit scene. I then tried subscribing to: EditorApplication.hierarchyChanged https://docs.unity3d.com/ScriptReference/EditorApplication-hierarchyChanged.html But it gets called after the prefab has already been closed and I need to run some code before the prefab scene is closed so that changes get written to the prefab upon exit. Anyone know how to do that?