semanticUI sidebar plus dropdown

Question

My project has some problem when I press the dropdown icon, my dropdown items are hidden by the white area, the pictures are more clearly. So I wonder if someone could fulfill my expectation, I would be appreciated.

Here's the part of the code:

<div class="ui sidebar inverte top five item menu">

    <div class="item">
        <div class="ui dropdown item" id="hideden-dropdown">
            类目
            <i class="dropdown icon"></i>
            <div class="menu">
                <a href="#" class="item">Electronics</a>
                <a href="#" class="item">Electronics</a>
                <a href="#" class="item">Electronics</a>
            </div>
        </div>
    </div>

    <a class="item">
        2
    </a>
    <a class="item">
        3
    </a>
    <a href="#" class="item">4</a>
    <a href="#" class="item">5</a>
</div>

<div class="pusher">
    <div class="ui button" id="menu">
        menu
    </div>

    <button type="button" name="button" class="ui red button" id="tran-bun">TestDimmer</button>

    <div class="ui segment" id="test-tran" style="margin:10%;">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore
        magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo
        consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
        pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est
        laborum.
    </div>
</div>


<script>
    $('#menu').click(function () {
        $('.sidebar')
                .sidebar('setting', 'transition', 'overlay')
                .sidebar('toggle')
        ;
    }),
            $(".ui.inline.dropdown").dropdown('show'),
            $('#hideden-dropdown').dropdown('show'),
            $('#test-tran')
                    .transition('jiggle')
    ;
</script>