Something broke in the way playlists are handled by the tag action window. Many different symptoms.
The playlist section of my tree looks something like:
Playlists
Car Radio
PlaylistGroup
PlaylistSubGroup1
Playlist1
Playlist2
PlaylistSubGroup2
Playlist3
etc.
PlaylistSubGroup3
etc.
SmartlistsGroup
Smartlist1
Smartlist2
etc.
Smartlists (stock)
StockSmartlist1
StockSmartlist2
etc.
Recently Imported
Web Media
Symptoms:
1) Adding playlists to customize tag action window always places the playlists at the bottom and it cannot be moved up. A work around is to add something else where you want it, say for example a divider, and then change the divider to playlists.
2) Not all PlaylistSubGroups are displayed in the tag action window. I can't make make rhyme or reason for why some are displayed and others are not. It might have something to do with PlaylistSubGroup having the same name as a custom view in the main tree, but I'm not sure. In my above example, the groups "Car Radio", "Smartlists (stock)", and one of my PlaylistSubGroups named "Device Media" is not not displayed in the tag action window.