mui-segmented-control中mui-slider-progress-bar在ios模拟器中会往下移动

这个segment是放在header里面的，在切换item的时候，在ios的模拟器中会自动往下移动，请问大神们，这是什么原因啊？

代码如下

<header class="mui-bar mui-bar-nav default-color">  
                    <a href="#offCanvasSide" class="mui-col-xs-3 mui-icon mui-icon-bars mui-pull-left default-color"></a>  
                    <!--<h1 class="mui-title">登录模板</h1>-->  
                    <div id="slider" class="mui-col-xs-6 mui-slider">  
                        <div id="sliderSegmentedControl" class="mui-slider-indicator mui-segmented-control mui-segmented-control-inverted">  
                            <a class="mui-control-item mui-active" href="#remeng">热门</a>  
                            <a class="mui-control-item" href="#guanzhu">关注</a>  
                        </div>  
                        <div id="sliderProgressBar" class="mui-slider-progress-bar mui-col-xs-6 highlight-background-color"></div>  
                        <div class="mui-slider-group" style="height: 0px;top:-2px">  
                            <div id="remeng" class="mui-slider-item mui-control-content mui-active">  

                            </div>  
                            <div id="guanzhu" class="mui-slider-item mui-control-content">  

                            </div>  
                        </div>  
                    </div>  
                    <button id='setting' class="mui-col-xs-3 mui-pull-right mui-btn-link default-color">  
                        <span class="mui-icon mui-icon-location"></span>  
                        常州  
                    </button>  
                </header>