The following article will explain how you can remove a certain button: http://www.telerik.com/help/aspnet-ajax/editor-removing-toolbar-buttons.html
You can find a list with the tools here: http://www.telerik.com/help/aspnet-ajax/editor-toolbar-intro.html
. "AboutDialog" is the about dialog.
The second article can also help you get started with building your own toolbars and these articles can expand on this:
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the UI for ASP.NET AJAX, subscribe to the blog feed