bool True if this component can be Previewed in its current state.
OnPreviewGUIを実装する場合はEditorを継承したクラスでオーバーライドします
ターゲットとなるアセットに応じて、プレビューを無効/有効にすることが出来ます。 The default implementation simply returns false, so if you override OnPreviewGUI you have to override this method as well. Note: Inspector previews are limited to the primary editor of persistent objects (assets), e.g., GameObjectInspector, MaterialEditor, TextureInspector. This means that it is currently not possible for a component to have its own inspector preview.