This might be considered a sort of special case of the issue described here: should arrows point left/down or down/up in collapsible accordion?
I have this scenario:

As can be seen in the illustration, my current design is inconsistent with the approach taken in Windows Explorer (and OSX Finder for that matter, just with other arrow icons).
So my question is:
- How to communicate that HEADLINE 1.1 controls the collapse-states of the contents of it's subheadlines and not if the subheadlines themselves are visible?
UPDATE: Here's a live example.
