dat.gui/elements/gui-row/gui-row.html

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

<polymer-element name="gui-row" attributes="name comment">

<template>

<div>

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

    <div id="row" class="comment-{{ comment != null }}" layout horizontal center>
        
        <div 
            id="name"
            on-mouseover="{{ openComment }}"
            on-mouseout="{{ closeComment }}"
            >
            <div id="nameInner">{{ name }}</div>
        </div>

        <div id="controller" flex>
            <content></content>
        </div>

    </div>

    <div id="comment" class="open-{{ commentOpen }}" hidden?="{{ comment == null }}">
        
        <div id="commentInner">{{ comment }}</div>

    </div>

</div>

</template>


</div>

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

</polymer-element>