If you are running XML Notepad on a PC that is running Microsoft's Internet Explorer version 5.0, you have the option of using some of the features provided under its DOM (Document Object Model). To choose the DOM you want to use, select Options from the Tools menu. The following dialogue box will appear:
See Using the IE5 DOM and Using the IE4 DOM for more information on what behavior changes occur with each DOM.
The Display Compatibility Warnings on Load option offers a reminder that will warn you of how your document may be affected if you open the file using the IE4 DOM.