diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index 4ec54d8dd..8f236bed6 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -46,7 +46,7 @@ module ProjectsHelper
     end
 
     options = ''
-    options << "<option value=''></option>" if project.allowed_parents.include?(nil)
+    options << "<option value=''>&nbsp;</option>" if project.allowed_parents.include?(nil)
     options << project_tree_options_for_select(project.allowed_parents.compact, :selected => selected)
     content_tag('select', options.html_safe, :name => 'project[parent_id]', :id => 'project_parent_id')
   end
diff --git a/config/initializers/10-patches.rb b/config/initializers/10-patches.rb
index 79641513e..d186bcdc4 100644
--- a/config/initializers/10-patches.rb
+++ b/config/initializers/10-patches.rb
@@ -91,6 +91,43 @@ end
 
 ActionView::Base.field_error_proc = Proc.new{ |html_tag, instance| html_tag || ''.html_safe }
 
+# HTML5: <option value=""></option> is invalid, use <option value="">&nbsp;</option> instead
+module ActionView
+  module Helpers
+    class InstanceTag
+      private
+      def add_options_with_non_empty_blank_option(option_tags, options, value = nil)
+        if options[:include_blank] == true
+          options = options.dup
+          options[:include_blank] = '&nbsp;'.html_safe
+        end
+        add_options_without_non_empty_blank_option(option_tags, options, value)
+      end
+      alias_method_chain :add_options, :non_empty_blank_option
+    end
+
+    module FormTagHelper
+      def select_tag_with_non_empty_blank_option(name, option_tags = nil, options = {})
+        if options.delete(:include_blank)
+          options[:prompt] = '&nbsp;'.html_safe
+        end
+        select_tag_without_non_empty_blank_option(name, option_tags, options)
+      end
+      alias_method_chain :select_tag, :non_empty_blank_option
+    end
+
+    module FormOptionsHelper
+      def options_for_select_with_non_empty_blank_option(container, selected = nil)
+        if container.is_a?(Array)
+          container = container.map {|element| element.blank? ? ["&nbsp;".html_safe, ""] : element}
+        end
+        options_for_select_without_non_empty_blank_option(container, selected)
+      end
+      alias_method_chain :options_for_select, :non_empty_blank_option
+    end
+  end
+end
+
 require 'mail'
 
 module DeliveryMethods
diff --git a/test/functional/boards_controller_test.rb b/test/functional/boards_controller_test.rb
index 910f16e9a..6b07b900c 100644
--- a/test/functional/boards_controller_test.rb
+++ b/test/functional/boards_controller_test.rb
@@ -117,7 +117,7 @@ class BoardsControllerTest < ActionController::TestCase
 
     assert_select 'select[name=?]', 'board[parent_id]' do
       assert_select 'option', (Project.find(1).boards.size + 1)
-      assert_select 'option[value=]', :text => ''
+      assert_select 'option[value=]', :text => '&nbsp;'
       assert_select 'option[value=1]', :text => 'Help'
     end
   end