When setting this to false, the launching of a pack crashes with this error:
http://pastebin.com/qeWGxWLG

This is the config

`bookshelves {
# Should the new varients be craftable? [default: true]
B:Crafting=true

# While enabled, new bookshelf varients for the other wood types will be added to the game [default: true]
B:Enabled=false

}

"player heads" {
# While enabled, variations of the vanilla mob heads will be added in the form of a new creative tab. [default: true]
B:Enabled=false
}`

Using Bookshelf-1.10-1.3.0.280

On Forge 1.10.2-12.18.0.2010

I know I'm using a 1.10 version on 1.10.2, but not setting those to false, and leaving them default, does allow the pack to launch.

PS: The crash also happens in 1.10 forge and its when setting to false the bookshelves.