Opening XML file and saving it changes the structure, why?

[neeirish]

I have a nice clean document with tags indented and structured so you can view them when you open your file. If I then open it in XMetal (6.0.1) and save it (that's all), XMetal puts everything into 4 lines that don't wrap.  This makes it impossible to compare the original file with the changed file. It also removes about 1/4 of the size (probably spaces).

How can you set it NOT to do this?

[Derek Read]

You have two options with your XMetaL customization (DTD/XSD + CSS + CTM + MCR + other files):

1) Turn pretty printing off for your customization. In this case the product should retain any existing pretty printing (essentially carriage returns) included with the file when it was opened. Any new content should be added without adding pretty printing.
2) Configure pretty printing for your customization to match the pretty printing put in place by the other software you are using to work with your XML.

Pretty printing is controlled by settings in the CTM file. Documentation on this is included with XMetaL Developer and the CTM editor is included with that product as well.