preceding-sibling error "...does not point to a valid location path of a field or group."

Question

I'm having a problem using the preceding-sibling in a conditional formatting condition.I have a secondary datasource that is a repeating table, and want to supress a column when it has the same value as the previous row's column, but the IP doesn't like my syntax.

The repeating table column's xpath is:
/dfs:myFields/dfsataFields/tns:Get_ContactFlagsResponse/tns:Get_ContactFlagsResult/NewDataSet/ContactCategory/lu_Group

My attempts at the preceding syntax have been based on  this syntax:
preceding-sibling::NodeName[1]/elementname

or
current()/preceding-sibling::NodeName[1]/elementname

both raise the same error in the conditional formatting designer.
"preceding-sibling::ContactCategory/lu_Group" does not point to a valid location path of a field or group.


A good article from Greg Collins http://www.infopathdev.com/blogs/greg/archive/2005/06/13/Using-XPath_2700_s-_2700_preceding_2D00_sibling_2700_-Axis-Correctly.aspx

Answer 1

This works:  preceding-sibling::*[1]/lu_Group

Answer 2

This helped me immensely. I knew it wasn't just copying the Xpath of the field, from examples I found.