When the contentPane is set to client="false", the renderer will only render content if the pane is selected. This is inoptimal because it means that the when a contentPane moves from opened to closed, a dom diff blanking the content is created, and the browser will never store the hidden content of the contentPane. This means that as a user is toggling back and forth in a tabSet or accordion, then we're always sending dom-diffs to blank out the hidden panes and show the selected panes whether or not the content has actually changed on the server or not. Over the course of switching panes this will probably use much more bandwidth than having contentPanes client="true".

If client="false" and the pane is not selected, but the pane has in the past been selected, we should continue to render it. This would allow the user to toggle quickly back and forth between panes, a central benefit of having client-side information.