Index: test/unit/lib/redmine/menu_manager/menu_item_test.rb
===================================================================
--- test/unit/lib/redmine/menu_manager/menu_item_test.rb	(リビジョン 8213)
+++ test/unit/lib/redmine/menu_manager/menu_item_test.rb	(リビジョン 8214)
@@ -114,7 +114,7 @@
 
   def test_has_children
     parent_item = get_menu_item(:test_menu, :parent)
-    assert parent_item.hasChildren?
+    assert parent_item.children.present?
     assert_equal 2, parent_item.children.size
     assert_equal get_menu_item(:test_menu, :child_menu), parent_item.children[0]
     assert_equal get_menu_item(:test_menu, :child2_menu), parent_item.children[1]
Index: config/environment.rb
===================================================================
--- config/environment.rb	(リビジョン 8213)
+++ config/environment.rb	(リビジョン 8214)
@@ -54,7 +54,6 @@
   # It will automatically turn deliveries on
   config.action_mailer.perform_deliveries = false
 
-  config.gem 'rubytree', :lib => 'tree'
   config.gem 'coderay', :version => '~>1.0.0'
 
   # Load any local configuration that is kept out of source control
Index: lib/redmine/menu_manager.rb
===================================================================
--- lib/redmine/menu_manager.rb	(リビジョン 8213)
+++ lib/redmine/menu_manager.rb	(リビジョン 8214)
@@ -15,93 +15,6 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
-require 'tree' # gem install rubytree
-
-# Monkey patch the TreeNode to add on a few more methods :nodoc:
-module TreeNodePatch
-  def self.included(base)
-    base.class_eval do
-      attr_reader :last_items_count
-
-      alias :old_initilize :initialize
-      def initialize(name, content = nil)
-        old_initilize(name, content)
-      	@childrenHash ||= {}
-        @last_items_count = 0
-        extend(InstanceMethods)
-      end
-    end
-  end
-
-  module InstanceMethods
-    # Adds the specified child node to the receiver node.  The child node's
-    # parent is set to be the receiver.  The child is added as the first child in
-    # the current list of children for the receiver node.
-    def prepend(child)
-      raise "Child already added" if @childrenHash.has_key?(child.name)
-
-      @childrenHash[child.name]  = child
-      @children = [child] + @children
-      child.parent = self
-      return child
-
-    end
-
-    # Adds the specified child node to the receiver node.  The child node's
-    # parent is set to be the receiver.  The child is added at the position
-    # into the current list of children for the receiver node.
-    def add_at(child, position)
-      raise "Child already added" if @childrenHash.has_key?(child.name)
-
-      @childrenHash[child.name]  = child
-      @children = @children.insert(position, child)
-      child.parent = self
-      return child
-
-    end
-
-    def add_last(child)
-      raise "Child already added" if @childrenHash.has_key?(child.name)
-
-      @childrenHash[child.name]  = child
-      @children <<  child
-      @last_items_count += 1
-      child.parent = self
-      return child
-
-    end
-
-    # Adds the specified child node to the receiver node.  The child node's
-    # parent is set to be the receiver.  The child is added as the last child in
-    # the current list of children for the receiver node.
-    def add(child)
-      raise "Child already added" if @childrenHash.has_key?(child.name)
-
-      @childrenHash[child.name]  = child
-      position = @children.size - @last_items_count
-      @children.insert(position, child)
-      child.parent = self
-      return child
-
-    end
-
-    # Wrapp remove! making sure to decrement the last_items counter if
-    # the removed child was a last item
-    def remove!(child)
-      @last_items_count -= +1 if child && child.last
-      super
-    end
-
-
-    # Will return the position (zero-based) of the current child in
-    # it's parent
-    def position
-      self.parent.children.index(self)
-    end
-  end
-end
-Tree::TreeNode.send(:include, TreeNodePatch)
-
 module Redmine
   module MenuManager
     class MenuError < StandardError #:nodoc:
@@ -169,7 +82,7 @@
 
       def display_main_menu?(project)
         menu_name = project && !project.new_record? ? :project_menu : :application_menu
-        Redmine::MenuManager.items(menu_name).size > 1 # 1 element is the root
+        Redmine::MenuManager.items(menu_name).children.present?
       end
 
       def render_menu(menu, project=nil)
@@ -181,7 +94,7 @@
       end
 
       def render_menu_node(node, project=nil)
-        if node.hasChildren? || !node.child_menus.nil?
+        if node.children.present? || !node.child_menus.nil?
           return render_menu_node_with_children(node, project)
         else
           caption, url, selected = extract_node_details(node, project)
@@ -306,13 +219,13 @@
       end
 
       def items(menu_name)
-        @items[menu_name.to_sym] || Tree::TreeNode.new(:root, {})
+        @items[menu_name.to_sym] || MenuNode.new(:root, {})
       end
     end
 
     class Mapper
       def initialize(menu, items)
-        items[menu] ||= Tree::TreeNode.new(:root, {})
+        items[menu] ||= MenuNode.new(:root, {})
         @menu = menu
         @menu_items = items[menu]
       end
@@ -398,7 +311,102 @@
       end
     end
 
-    class MenuItem < Tree::TreeNode
+    class MenuNode
+      include Enumerable
+      attr_accessor :parent
+      attr_reader :last_items_count, :name
+
+      def initialize(name, content = nil)
+        @name = name
+        @childrenHash ||= {}
+        @children = []
+        @last_items_count = 0
+      end
+
+      def children
+        if block_given?
+          @children.each {|child| yield child}
+        else
+          @children
+        end
+      end
+
+      # Returns the number of descendants + 1
+      def size
+        @children.inject(1) {|sum, node| sum + node.size}
+      end
+
+      def each &block
+        yield self
+        children { |child| child.each(&block) }
+      end
+
+      # Adds a child at first position
+      def prepend(child)
+        raise "Child already added" if @childrenHash.has_key?(child.name)
+  
+        @childrenHash[child.name]  = child
+        @children = [child] + @children
+        child.parent = self
+        return child
+      end
+
+      # Adds a child at given position
+      def add_at(child, position)
+        raise "Child already added" if @childrenHash.has_key?(child.name)
+  
+        @childrenHash[child.name]  = child
+        @children = @children.insert(position, child)
+        child.parent = self
+        return child
+      end
+
+      # Adds a child as last child
+      def add_last(child)
+        raise "Child already added" if @childrenHash.has_key?(child.name)
+  
+        @childrenHash[child.name]  = child
+        @children <<  child
+        @last_items_count += 1
+        child.parent = self
+        return child
+      end
+
+      # Adds a child
+      def add(child)
+        raise "Child already added" if @childrenHash.has_key?(child.name)
+  
+        @childrenHash[child.name]  = child
+        position = @children.size - @last_items_count
+        @children.insert(position, child)
+        child.parent = self
+        return child
+      end
+      alias :<< :add
+
+      # Removes a child
+      def remove!(child)
+        @childrenHash.delete(child.name)
+        @children.delete(child)
+        @last_items_count -= +1 if child && child.last
+        child.parent = nil
+        child
+      end
+
+      # Returns the position for this node in it's parent
+      def position
+        self.parent.children.index(self)
+      end
+
+      # Returns the root for this node
+      def root
+        root = self
+        root = root.parent while root.parent
+        root
+      end
+    end
+
+    class MenuItem < MenuNode
       include Redmine::I18n
       attr_reader :name, :url, :param, :condition, :parent, :child_menus, :last