After I create a Hierarchical MetaData Tree, I would like to be able to go back and edit it.

Currently, I can edit the Title and Description, but I can't Add, Remove or change the order of Tags, and I can't change what it is limited to (Video, Music, Photo). The workaround is to create a new one and delete the old, but with 10K tracks that takes several minutes.

To Repro:
Create the PlayList:
Right-Click 'My Music' Folder > Add > Dynamic Playlist > Hierarchical MetaData Tree
Customise the PlayList, Click Ok
Edit the Playlist:
Right-Click the new Playlist > Properties

The Metadata columns to the left (included) and right (available) can be selected.
But the buttons to Add, Remove, etc., are greyed out.
The 'Limit To' Check boxes are also greyed out.

Also, those metadata columns should have titles, although it is obvious what they are.