[xwiki-users] need advice about an extension developpment

Hello, I try to writing an extension to add the right panel collapsible (with CSS only). Something like this: http://www.cssportal.com/css3-preview/demo/css-menu-ex4.html (hide and seek panel) explained here http://www.cssportal.com/css3-preview/showing-and-hiding-content-with-pure-… I inserted code in rightpanels.vm and CSS but the limitation is when I navigate on another xwiki page/space the right panel is reset. My right panel is not persistent. Do you have an advice to make my right panel persistent: - if user show panel and change current page, right panel must be still open - if user hide panel and change current page right panel must be still hide javascript (and cookie) are mandatory in my case? Do you have an elegant tip: an secret xwiki API ? Thxs Pascal B