for position: fixed and changed stacking contexts, you're likely running into this:<p><a href="http://updates.html5rocks.com/2012/09/Stacking-Changes-Coming-to-position-fixed-elements" rel="nofollow">http://updates.html5rocks.com/2012/09/Stacking-Changes-Comin...</a><p>Basically, the position: fixed on the parent of the span you're trying to put on top is now making the parent its own stacking context, which means that all children will be stacked relative to each other, not to the first absolutely or relatively positioned ancestor of the parent, as it was before.<p>The easiest fix is to set the z-index on the parent, since that will correctly stack it relative to its sibling (your other position: fixed element). The other way is to give the sibling that you want to be below the other content a negative z-index, since that will, again, specify it in the stacking context you want to affect. Both of these fixes should render correctly in older browsers (I believe).<p>This is annoying when it affects existing content, but it is part of the spec now (and it's apparently how mobile browsers have always rendered it).