Don't collapse the DOM tree when the a query does not match any nodes.

[GoogleCodeExporter]

When typing an xPath to be evaluated, it would be helpful if the DOM didn't 
collapse/reset back to the root.  Perhaps there can be some visual indication 
that the xQuery is either a) syntactically incorrect or b) didn't find 
anything.  I noticed the red paint of the eval entry field when the syntax is 
wrong.  Something similar for an xQuery that is valid but doesn't return 
anything would be nice.

Original issue reported on code.google.com by [email protected] on 20 Jul 2011 at 4:16