Prioritizing a cell not working for small

[kelsheikh]

Can't seem to get this to work properly in the example for 'Prioritizing a Cell'. Works with larger views but won't push 'Sidebar' down on important(small).

<div class="row">
	<div class="4u 12u$(small)">
		Sidebar
	</div>
	<div class="8u$ 12u$(small) important(small)">
		Main Content
	</div>
</div>