Re: Getting the first preceding-sibling with a specifi

   preceding-sibling::x[title][1]

This will select the first x element (counting backwards) that has a
title. (so will return at most 1 node)

   preceding-sibling::x/title[1]

This will select the first title element of each of the selected x
elements so will return any number of nodes.

  (preceding-sibling::x/title)[1]

This will select the first title elemnt (in document order) that is a
child of the preceding sibling x elements (so will return at most 1
node)