Scoping based on whether we are in spree's admin backend or not.

application.rb

#Make sure this appears somewhere in your application.rb file.

    config.to_prepare do
      # Load application's model / class decorators
      Dir.glob(File.join(File.dirname(__FILE__), "../app/**/*_decorator*.rb")) do |c|
        Rails.configuration.cache_classes ? require(c) : load(c)
      end

      # Load application's view overrides
      Dir.glob(File.join(File.dirname(__FILE__), "../app/overrides/*.rb")) do |c|
        Rails.configuration.cache_classes ? require(c) : load(c)
      end
    end

base_controller_decorator.rb

#put in app/controllers/spree/base_controller_decorator.rb

Spree::BaseController.class_eval do

  before_filter :store_path_in_thread

  def store_path_in_thread
    Thread.current[:path] = request.original_url
  end
end

taxon_decorator.rb

Spree::Taxon.class_eval do
  scope :with_children, :conditions => "parent_id is null OR #{self.table_name}.id IN (SELECT taxon_id FROM spree_products_taxons)"

  def self.scope_based_on_path
    path = Thread.current[:path]

    if path.nil? or path.include? "admin"
      order("#{self.table_name}.position")
    else
      #binding.pry
      with_children
      #order("#{self.table_name}.position")
    end
  end

  scope :base_on_path, lambda { scope_based_on_path }

  default_scope -> { base_on_path }
end