Thank you Guillaume! It works now! Hello Marius, I have improved the document http://platform.xwiki.org/xwiki/bin/view/AdminGuide/WysiwygEditor by giving an example how to add a new button to the toolbar of WYSIWYG editor. At first, I thought only Xwiki people who created Xwiki can edit the document. Today I tried to register and I know I can edit it too! That's great! I also can write a document about how to Load GWT application to Xwiki page, do you know where should I place this new document? Should I place it in a existing page or should place create a new page? Marius, I will digest what your replied last time. Thank you! :-D PS: I will be in China during Dec 26 ~ Jan 11, 2011, if anyone xwiki people have a chance to come to Beijing let me know I will should you around. Have a nice week everyone!