10.1 Plugin Manager : Sub Folders tip
To create Sub Folders inside folders in the new 10.1 Plugin Manager
1 Logic Pro X > Preferences > Plugin Manger
2 click on the + sign in the upper left menu and a new folder Untitled will be generated.
3 rename the folder and hit Return.
4 Create nested folders by creating a new folder adding a colon to an existing folder name e.g. For a folder named Synths create subfolders Synths:Subtractive , Synths:Modeling etc.
5 Once you have the folders created and labeled, then its easy just to drag and drop from the Show All or Manufacturer menus to populate the folders, or delete them as necessary. If you always can also put oft used plugins in the Top Level and they will be directly in the menu and not in a folder.
Thanks to Artzeal on LPH fior this great little undocumented 'hack'
So, this is what you will see after doing so...
Then give you this when you click on the Insert Button in a track strip
Logic Pro X, OS X Yosemite (10.10.1), 10.10.2 Beta 6