Broken responsive menu on Minify

Hi, i have a responsive website and i have activaded w3c total cache.
whenever i Minify, the responsive menu is misssing.
This menu activates on specific screen sizesm the code is:

<div class="main-nav">
	<div id="responsive_current_menu_item">Welcome to Yum Yum Videos!</div>
	<ul id="menu-top-menu" class="menu">
		<li>...</li>
	</ul>
	<a id="responsive_menu_button"></a>
</div>

The problem is, that whenever i minify, the id=”responsive_current_menu_item” and id=”responsive_menu_button” simply dissapear from code.

you can see it in action here (is the top menu, w3c tocal cache is deactivated in order to show responsive menu)

any idea where i might take a look please?

http://ww.wp.xz.cn/plugins/w3-total-cache/