jquery autocomplete list does not stick with parent input element

I'm having some difficulty adapting jqueryUI autocomplete to my site's CSS layout.

Whenever I call the autocomplete function onto an input field, the list opens as expected. Since the input lives within a div that is of fixed height, when the user scrolls that div, the autocomplete list stays fixed.

Has anyone encountered this and know of a workaround? This issue does not occur when the parent div is not fixed in height.

I've made a jsfiddle mockup here: http://jsfiddle.net/NSm7f/1/

here is my sample code:

<div class="root">
    <div id="Header">
        <div class='heading'>Test</div>
    </div>
    <div class='box' id="Wrapper">
        <div class='box' id="Leftpanel">
            <p>some text</p>
                <h1>Other stuff</h1>

            <br>
            <br>Autocomplete box:
            <input id="box1">
            <p>some text</p>
                <h1>Other stuff</h1>

            <br>
            <br>Another autocomplete:
            <input id="box2">
            <p>some text</p>
                <h1>Other stuff</h1>

            <br>
            <br>
            <p>some text</p>
                <h1>Other stuff</h1>

            <br>
            <br>
            <p>some text</p>
                <h1>Other stuff</h1>


            <br>
            <br>
        </div>
        <!--Leftpanel-->
        <div class='box' id="Rightpanel">
            <form>
                <textarea rows="33" cols="45"></textarea>
                <br>
            </form>
        </div>
        <!--End rightpanel-->
    </div>
    <!--wrapper-->
</div>
<!--root-->

My JS (yes, I have jqueryUI and the default jqueryUI css loaded):

 $("#box1").autocomplete({
     source: ['Skull,Nasal', 'Skull,Lacrimal', 'Skull,Inferior Nasal Concha', 'Skull,Maxiallary', 'Skull,Zygomatic', 'Skull,Temporal', 'Skull,Palatine', 'Skull,Parietal', 'Skull,Malleus', 'Skull,Incus', 'Skull,Stapes', 'Skull,Frontal', 'Skull,Ethmoid', 'Skull,Vomer', 'Skull,Sphenoid', 'Skull,Mandible', 'Skull,Occipital', 'Rib 1', 'Rib 2', 'Rib 3', 'Rib 4', 'Rib 5', 'Rib 6', 'Rib 7', 'Rib 8 ', 'Rib 9 ', 'Rib 10 ', 'Coccyx']
 });

 $("input#box2").autocomplete({
     source: ['Skull,Nasal', 'Skull,Lacrimal', 'Skull,Inferior Nasal Concha', 'Skull,Maxiallary', 'Skull,Zygomatic', 'Skull,Temporal', 'Skull,Palatine', 'Skull,Parietal', 'Skull,Malleus', 'Skull,Incus', 'Skull,Stapes', 'Skull,Frontal', 'Skull,Ethmoid', 'Skull,Vomer', 'Skull,Sphenoid', 'Skull,Mandible', 'Skull,Occipital', 'Rib 1', 'Rib 2', 'Rib 3', 'Rib 4', 'Rib 5', 'Rib 6', 'Rib 7', 'Rib 8 ', 'Rib 9 ', 'Rib 10 ', 'Coccyx']
 });

and my css:

.box {
    float: left;
}
#root {
    max-width: 1200px;
    margin: 0 auto;
}
#Wrapper {
    width: 100%;
    display: table;
}
#Leftpanel, #Rightpanel {
    vertical-align: top;
}
#Leftpanel {
    width: 57%;
    display: table-cell;
    height:750px;
    color: #B29D72;
    overflow:scroll;
    background-color: #272F44;
    -moz-border-radius: 2px;
    border-radius: 5px;
    padding: 1%;
    margin:0.5%
}
#Rightpanel {
    width: 37%;
    display: table-cell;
    height: 750px;
    color: #B2A283;
    background-color: #0D162C;
    -moz-border-radius: 5px;
    border-radius: 5px;
    padding: 1%;
    margin:0.5%
}
#Sidebar {
    width: 15%;
    background-color: #B2A283;
    color: #0D162C;
    padding:1%;
    margin:0.5%;
    -moz-border-radius: 2px;
    border-radius: 5px;
}
#Sidebar a:link {
    color: #FFF4CB;
}
#Footer {
    width: 97%;
    height: auto;
    background-color: #B2A283;
    color: #0D162C;
    padding: 1%;
    margin: 0.5%;
    -moz-border-radius: 2px;
    border-radius: 5px;
}
#Footer a:link {
    color: #FFF4CB;
    padding-left: 5px;
    padding-right: 5px;
}
#Footer A:hover {
    color: #CA9221;
}
#Sidebar .slide-out-div {
    padding: 20px;
    width: 250px;
    background: #ccc;
    border: 1px solid #29216d;
}