Bootstrap 3选项卡：未显示下拉菜单

Question

以下是Bootstrap选项卡的html代码的一部分：

           <div class="collapse navbar-collapse" id="navbarCollapse1">
              <!--<ul class="nav navbar-nav">-->
              <ul class="nav navbar-nav" data-toggle="collapse-nav" data-target="#more-menu-allowed">


              <li class="dropdown">
                <a id="dropdownuser" href="#" data-toggle="dropdown" class="dropdown-toggle" data-toggle="tooltip" data-placement="bottom" ><span class="glyphicons glyphicons-cogwheel text-danger"></span> <%=t('Time Sheets') %> <b class="caret" id="caret_medium"></b></a>
                <ul id="namelist" class="dropdown-menu" role="menu"></ul>
                <ul class="dropdown-menu">
                  <li><%= link_to "<i class='glyphicon glyphicon-list'></i> #{I18n.t('List')}".html_safe, SUBURI + "/view_handler?index=1&url=#{ pay_timex.time_sheets_path}" if has_action_right?('index', 'pay_timex/time_sheets') %></li>
                  <li><%= link_to "<i class='glyphicon glyphicon-plus'></i> #{I18n.t('New')}".html_safe, SUBURI + "/view_handler?index=1&url=#{ pay_timex.new_time_sheet_path}" if has_action_right?('new', 'pay_timex/time_sheets') %></li>
                  <li><%= link_to "<i class='glyphicon glyphicon-list-alt'></i> #{I18n.t('Search')}".html_safe, SUBURI + "/view_handler?index=1&url=#{ pay_timex.search_time_sheets_path}" if has_action_right?('search', 'pay_timex/time_sheets') %></li>                
                </ul>
              </li>
            ......

标签显示正常。但是，单击选项卡时，下拉菜单未显示（显示小的重叠）。什么可以使下拉菜单再次显示？

更新

标签图片：