Fix parent menu item preselection of grand children of a wiki page

app/controllers/wiki_menu_items_controller.rb

@@ -96,10 +96,11 @@ class WikiMenuItemsController < ApplicationController
     possible_parent_menu_items = WikiMenuItem.main_items(@page.wiki.id) - [@wiki_menu_item]
 
     @parent_menu_item_options = possible_parent_menu_items.map {|item| [item.name, item.id]}
-    @selected_parent_menu_item = if @wiki_menu_item.parent
+
+    @selected_parent_menu_item_id = if @wiki_menu_item.parent
       @wiki_menu_item.parent.id
-    elsif @page.parent && menu_item_of_parent_page = possible_parent_menu_items.detect {|item| item.title == @page.parent.title}
-      menu_item_of_parent_page.id
+    else
+      @page.nearest_parent_menu_item(:is_main_item => true).try :id
     end
   end
 end

app/models/wiki_page.rb

@@ -209,10 +209,20 @@ class WikiPage < ActiveRecord::Base
   def nearest_menu_item
     if self.menu_item
       self.menu_item
-    elsif self.parent
-      self.parent.nearest_menu_item
     else
-      nil
+      nearest_parent_menu_item
+    end
+  end
+
+  def nearest_parent_menu_item(options={})
+    return nil unless self.parent
+
+    options = options.with_indifferent_access
+
+    if (parent_menu_item = self.parent.menu_item) && (!options[:is_main_item] || parent_menu_item.is_main_item?)
+      parent_menu_item
+    else
+      self.parent.nearest_parent_menu_item
     end
   end
 

app/views/wiki_menu_items/edit.html.erb

@@ -65,7 +65,7 @@ See doc/COPYRIGHT.rdoc for more details.
       <% disabled = @parent_menu_item_options.empty? %>
       <%= form.radio_button 'setting', :sub_item, :disabled => disabled %>
       <%= form.label 'setting_sub_item', l(:label_wiki_show_submenu_item), {:id => 'with-select'} %>
-      <%= select_tag "parent_wiki_menu_item", options_for_select(@parent_menu_item_options, @selected_parent_menu_item), :disabled => disabled %>
+      <%= select_tag "parent_wiki_menu_item", options_for_select(@parent_menu_item_options, @selected_parent_menu_item_id), :disabled => disabled %>
     </p>
   </fieldset>
   <p>