学生没有课程和项目时，课程和项目导航有2条线

app/views/layouts/new_base_user.html.erb

@@ -109,9 +109,9 @@
               <% end%>
           <% end%>
         </div>
-        <div class="homepageLeftMenuCourses" id="homepageLeftMenuCourses">
+        <% courses = @user.courses.visible.select("courses.*,(SELECT MAX(created_at)  FROM `course_activities` WHERE course_activities.course_id = courses.id) AS a").order("a desc").limit(5)%>
+        <div class="homepageLeftMenuCourses <%= courses.empty? ? 'none' : ''%>" id="homepageLeftMenuCourses">
           <ul>
-            <% courses = @user.courses.visible.select("courses.*,(SELECT MAX(created_at)  FROM `course_activities` WHERE course_activities.course_id = courses.id) AS a").order("a desc").limit(5)%>
             <%= render :partial => 'layouts/user_courses', :locals => {:courses => courses,:user => @user, :page => 0} %>
           </ul>
         </div>
@@ -122,9 +122,9 @@
               <%=link_to "", new_project_path, :class => "homepageMenuSetting fr", :title => "新建项目"%>
           <% end%>
         </div>
-        <div class="homepageLeftMenuCourses" id="homepageLeftMenuForge">
+        <% projects = @user.projects.visible.select("projects.*,(SELECT MAX(created_at)  FROM `forge_activities` WHERE forge_activities.project_id = projects.id) AS a").order("a desc").limit(5)%>
+        <div class="homepageLeftMenuCourses <%= projects.empty? ? 'none' : ''%>" id="homepageLeftMenuForge">
           <ul>
-            <% projects = @user.projects.visible.select("projects.*,(SELECT MAX(created_at)  FROM `forge_activities` WHERE forge_activities.project_id = projects.id) AS a").order("a desc").limit(5)%>
             <%= render :partial => 'layouts/user_projects', :locals => {:projects => projects,:user => @user, :page => 0} %>
           </ul>
         </div>