Hi Marius, I successfully load the tree panel in the WYSIWYG editing model. Thank you so much! :-) I put the compiled xwiki-web-gwt, xwiki-web-wysiwyg and xwiki-webdav 2.02 jar file to the lib folder. After the tree loaded, I found there 2 errors using firebug (thank you for recommendation), one is saying "isc is not defined" in overwritesc.js(), one is saying "isc is not defined" in overwritesc.js(). Here is the screenshot: http://picasaweb.google.com/lh/photo/BxK7IksttDQFB4KtJAJOvg?feat=directlink. Here is what I did, first I modify the template/macros.vm file: Wysiwyg.onModuleLoad(function() { window["wysiwyg_editor"] = new WysiwygEditor($jsVarName); $jsVarName = undefined; }); In the GWT file: native void setBackgroudColor(String color) /*-{ wysiwyg_editor.getCommandManager().execute('backcolor', 'yellow'); alert(wysiwyg_editor.getCommandManager().getValue('backcolor') ); }-*/; /** * This is the entry point method. */ @SuppressWarnings("unchecked") public void onModuleLoad() { Tree tree = new Tree(); tree.setAnimationEnabled(true); TreeItem outerRoot = new TreeItem("DR Tag Tree"); outerRoot.addItem("Alternative"); outerRoot.addItem("Assumption"); outerRoot.addItem("Argument"); outerRoot.addItem("Claim"); outerRoot.addItem("Decision"); outerRoot.addItem("Requirement"); tree.addItem(outerRoot); tree.addSelectionHandler(new SelectionHandler() { public void onSelection(SelectionEvent event) { if (((TreeItem) event.getSelectedItem()).getText().equals( "Alternative")) { setBackgroudColor("yellow"); } else if (((TreeItem) event.getSelectedItem()).getText() .equals("Requirement")) { setBackgroudColor("blue"); } else if (((TreeItem) event.getSelectedItem()).getText() .equals("Decision")) { setBackgroudColor("green"); } Window.alert(((TreeItem) event.getSelectedItem()).getText()); } }); Could you give me some ideas what is wrong? Or what I missed? Thank you, Marius! -Leon