CSS issue when embeding flexible layout inside a flexible layout.

I have a flexible panel with a left hand sidebar embedded in a flexible layout with a right hand sidebar.

The problem is the top sidebar is impacting on the inner one. This patch makes a small change to the css so that it will only impact on the immediate div.panel-flexible-sidebars below the div with the pane id.

I have use > to do this, but I am not 100% sure how this will be in cross browser.