module Spree
  class ProductsController < Spree::StoreController
    before_filter :load_product, :only => :show
    before_filter :load_taxon, :only => :index

    rescue_from ActiveRecord::RecordNotFound, :with => :render_404
    helper 'spree/taxons'

    respond_to :html

    def index
      @searcher = build_searcher(params)
      @products = @searcher.retrieve_products
      @taxonomies = Spree::Taxonomy.includes(root: :children)
    end

    def show
      @variants = @product.variants_including_master.active(current_currency).includes([:option_values, :images])
      @product_properties = @product.product_properties.includes(:property)
      @taxon = Spree::Taxon.find(params[:taxon_id]) if params[:taxon_id]
    end

    private
      def accurate_title
        @product ? @product.name : super
      end

      def load_product
        if try_spree_current_user.try(:has_spree_role?, "admin")
          @products = Product.with_deleted
        else
          @products = Product.active(current_currency)
        end
        @product = @products.friendly.find(params[:id])
      end

      def load_taxon
        @taxon = Spree::Taxon.find(params[:taxon]) if params[:taxon].present?
      end
  end
end

module Spree
  class ProductsController < Spree::StoreController
    before_filter :load_product, :only => :show
    rescue_from ActiveRecord::RecordNotFound, :with => :render_404
    helper 'spree/taxons'

    respond_to :html

    def index
      @searcher = build_searcher(params)
      @products = @searcher.retrieve_products
      @taxonomies = Spree::Taxonomy.includes(root: :children)
    end

    def show
      @variants = @product.variants_including_master.active(current_currency).includes([:option_values, :images])
      @product_properties = @product.product_properties.includes(:property)
      @taxon = Spree::Taxon.find(params[:taxon_id]) if params[:taxon_id]
    end

    private
      def accurate_title
        @product ? @product.name : super
      end

      def load_product
        if try_spree_current_user.try(:has_spree_role?, "admin")
          @products = Product.with_deleted
        else
          @products = Product.active(current_currency)
        end
        @product = @products.friendly.find(params[:id])
      end
  end
end

--- 
+++ 
@@ -1,6 +1,8 @@
 module Spree
   class ProductsController < Spree::StoreController
     before_filter :load_product, :only => :show
+    before_filter :load_taxon, :only => :index
+
     rescue_from ActiveRecord::RecordNotFound, :with => :render_404
     helper 'spree/taxons'
 
@@ -31,5 +33,9 @@
         end
         @product = @products.friendly.find(params[:id])
       end
+
+      def load_taxon
+        @taxon = Spree::Taxon.find(params[:taxon]) if params[:taxon].present?
+      end
   end
 end
[frontend] Load taxon if params[:taxon] exists in ProductsController

Fixes a small bug where searching *twice* for the same term results in the taxon 'scope' being forgotten
