edit page

Hi, i use since few days the great xwiki platform on xwiki.com<http://xwiki.com>( http://jguard.xwiki.com). but i've got one problem about editing a page: when i edit a page, i can modify content, click on 'preview' and 'save' the page: => the content is updated. when i edit a page, modify content but not click on 'preview' but click directly on the 'save' button, the content is not updated. when i modify a page, click on 'preview', 'save', and want to modify one more time the page, the code of the page is the code of the old page. is there any problem on cache settings? have you one tips to solve this problem? thanks to the xwiki team, for the wiki solution, and the free hosting offer! cheers, Charles(jGuard team).