dat.gui/elements/gui-panel/gui-panel.html

<link rel="import" href="../../../polymer/polymer.html">
<link rel="import" href="../gui-row/gui-row.html">

<polymer-element 
    name="gui-panel"
    attributes="docked autoplace open">

<template>

<link rel="stylesheet" href="gui-panel.css">

<div id="container" class="docked-{{ docked }} autoplace-{{ autoPlace }} open-{{ open }}">
    <div id="controllers">
        <content></content>
    </div>
    <div id="closeButton" on-tap="{{ tapClose }}" hidden?="{{ docked }}">{{ open ? 'Close' : 'Open' }} Controls</div>
</div>

</template>

</div>

<script src="gui-panel.js"></script>

</polymer-element>