Get default preview for GameObject Editor

So I created a custom Editor that ABSOLUTELY must be a GameObject editor, I.E. it replaces the base editor for GameObjects.
I used the OnInspectorGUI override and base.DrawDefaultInspector() to get the default inspector back.
However I cannot for the life of me get the preview to show up, and it even makes the preview icons turn back into blue boxes.

So far I have tried the following thiongs.
Attempted to draw a custom preview, no success without drawing a literal custom preview, this will never bring icons back.
Tried including the base.OnPreviewGUII.
Tried including the base.OnInteractivePreviewGUI.
Tried including the base.OnPreviewSettings.
Tried using OnGUI to draw the preview from editor… still no luck.
Tried incorporating ALL of the above at once, no luck.
Any ideas? People are going to be very unhappy when they realize that my extensions does not show preview GUI.

Any thoughts? @Bunny83

Please see my answer here.

The problem is that you need to re-implement Editor.RenderStaticPreview(). Simply calling the base implementation will not help you because you are not inheriting from the built-in GameObjectInspector class, but simply Editor, which will just draw a cube icon instead of a preview of the renderers.

The best workaround for now is to create an instance of the built-in GameObjectInspector (via reflection) using your same targets in e.g., OnEnable, and call RenderStaticPreview on this instance and return its result in your method.

@RobAnthem I’ve just finished my own preview asset, maybe it will be useful for you: https://forum.unity3d.com/threads/powerful-preview.460157/