In case you missed it, Microsoft resurrected the old XML Notepad last year. The new version, XML Notepad 2007, is a .NET 2.0 application for which source code is available on CodePlex. I find it the application quite useful. You can find the links to XML Notepad 2007 at the Microsoft XML Developer Center site. In an August 2006 article on MSDN, Chris Lovett, the principal developer of the appllication You can find the links to XML Notepad 2007 at the Microsoft XML Developer Center site. In an August 2006 article on MSDN, Chris Lovett, the principal developer of the appllication, discussses its design.What does it do? According to the author: XML Notepad 2007 provides a simple intuitive User Interface for browsing and editing XML documents. Handy features include: Tree View synchronized with Node Text View for quick editing of node names and values. Incremental search (Ctrl+I) in both tree and text views, so as you type it navigates to matching nodes. Cut/copy/paste with full namespace support. Drag/drop support for easy manipulation of the tree, even across different instances of XML Notepad and from the file system. Infinite undo/redo for all edit operations. In place popup multi-line editing of large text node values. Configurable fonts and colors via the options dialog. Full find/replace dialog with support for regex and XPath. Good performance on large XML documents, loading a 3mb document in about one second. Instant XML schema validation while you edit with errors and warnings shown in the task list window. Intellisense based on expected elements and attributes and enumerated simple type values. Support for custom editors for date, dateTime and time datatypes and other types like color. Handy nudge tool bar buttons for quick movement of nodes up and down the tree. Inplace HTML viewer for processing Built-in XML Diff tool. Support for XInclude. Dynamic help from XSD annotations. Goto definition to navigate includes and XSD schema information. What can you learn from the source code? The short summary is how to implement all of the above; I think that the code that processes XML is quite elegant, and a good starting point for people writing other XML processing applications. On the other hand, don’t expect too much: I wasn’t able to build the version 465 project I downloaded from CodePlex without errors in my copy of Visual Studio 2005. I wasn’t able to bring up the forms in design view, and all the unit tests failed. There has been a new build posted in the last few days; I hope that will fix the problem. Software Development