While investigating another bug, I noticed that the

 element is not respecting the formatting of the element more than once.   If I add the following 

{code:xml}
<test>
    <another tag="attribute"/>
</test>

to a page I'm editing and select save then the formatting (i.e. indenting) is correctly displayed. However, if I try and edit the page again then the formatting is gone and all the elements start in 1st column.