Hi Peter, oXygen provide also a tree based editor that is available as a tool, see Tools->Tree Editor (CTRL+T) and also as a separate application see the Oxygen Tree Editor (treeEditor.exe) launcher. Please try also that and see if that helps. It will be interesting for us to perform some tests with your file that you had problems with so if you can make that available please let us know on support@oxygenxml.com how to get access to it (it will not work to just attach it to an email). One thing that may render the format and indent on open useless is the possible presence of an xml:space="preserve" attribute eventually on the root element or on some element with a large content. Best Regards, George -- George Cristian Bina <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger http://www.oxygenxml.com