How to expand all (or descendants of selected) node of a plist at once?
Select a node and press Option + Right Arrow. Collapsing is Option + Left Arrow.
See https://superuser.com/questions/76509/expanding-to-all-in-xcode-projects-groups for corroboration on this answer.
Excerpt from the xcode 3.1 update:http://lists.apple.com/archives/xcode-users/2008/Jul/msg00273.html
I can not try it right now with my phone but i guess this is still working.
Selecting a Property List file in the Groups and Files or Detail view now opens the file in a tabular outline instead of text form, regardless of whether the property list is in old-style text, XML, or binary format. You can expand and collapse the arrays and dictionaries in the property list as in any outlining tool, and edit the keys and values. Option-click the disclosure arrows to Expand All or Collapse All.