Saved Notebooks no longer allow user to add snippets, also show Hive Editor history

From Hue 4.7 (and still present in 4.8 as verified on demo.gethue.com), saved Notebooks from the notebook editor do not allow the user to add additional snippets.

• Open notebook Editor
• Add one or more snippet types (Hive, Scala, etc)
• Save as Document
• Open Document Browser
• Load saved Notebook Document
• The Notebook shows up, but does not allow the user to add more snippets to it or edit it outside of changing the existing queries.  This is broken vs. Hue 4.6 where the user could add snippets to a saved notebook.

Additionally, when loading Documents that were saved from the Notebook Editor, they are showing up in their various Editor types instead of the Notebook Editor.  I.e. a saved Scala snippet is showing up in the Scala Editor once opened from the Document Browser, and not in the Notebook Editor.  Same for Hive, etc.

Lastly, elements of the various Editors are showing up in Saved Notebooks.  Principally, the Hive Editor document query history pane is showing up in saved Notebooks when they are opened from the Document browser, and a Hive snippet exists in the Notebook.

This is making the Notebook Editor not very useful for users, and makes it hard for them to work with archived notebooks saved prior to Hue 4.7.