Fix several bus when there is no design

lib/parsers/parser_back_end.rb

@@ -47,9 +47,9 @@ module ParserBackEnd
         ret << "'></div>"
       else
         part = page.page_parts.detect{ |p| p.name.to_s == content['name'].to_s } rescue nil
-        ret << "<div id='#{content['name']}' part_id='#{part.id}' class='editable' style='border:solid 1px; margin:5px; padding:5px;'>"
+        ret << "<div id='#{content['name']}' part_id='#{part.id}' class='editable' style='border:solid 1px; margin:5px; padding:5px;'>" if part
         ret << "<div class='edit_link' style='display:none'>"
-        ret << " <a href='#{edit_admin_page_part_path(part.id)}' class='nav'>#{t(:edit)}</a>"
+        ret << " <a href='#{edit_admin_page_part_path(part.id)}' class='nav'>#{t(:edit)}</a>" if part
         ret << '</div>'
         case part.kind
         when 'text'
@@ -65,7 +65,7 @@ module ParserBackEnd
           public_r_tags << part.public_r_tag
         else
             ''
-        end
+        end if part
       end
       scope = "<#{content.name}"
       content.attributes.each_pair do |key, value|

lib/parsers/parser_front_end.rb

@@ -61,7 +61,7 @@ module ParserFrontEnd
           public_r_tags << part.public_r_tag
         else
             ''
-        end
+        end if part
       end
       scope = "<#{content.name}"
       content.attributes.each_pair do |key, value|