Hi Marius, I integrate the tree in the latest XE snapshot, it works! Thank you! Where can I find the color vocabulary specified by your API? Can I use hex number to specify color? It seems the snapshot version can not save document and it will automatically generate so many sessions. It only works on my Dell pc, does not work on the linux server. If I try to save document (on linux I even can not create and save edit panel) it will prompt me this error: HTTP Status 500 - ------------------------------ *type* Exception report *message* ** *description* *The server encountered an internal error () that prevented it from fulfilling this request.* *exception* java.lang.StringIndexOutOfBoundsException: String index out of range: -1 java.lang.String.substring(Unknown Source) java.lang.String.substring(Unknown Source) com.xpn.xwiki.web.ActionFilter.getTargetURL(ActionFilter.java:167) com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:105) com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68) com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:295) com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112) Next Friday it is our University Graduate Forum, I have a poster presentation. Do you need me to print and hand out flyer of Xwiki to people to give Xwiki a advertisement? Really appreciate your help! Have a nice weekend! -Leon