Hi Klaus,
don't worry. For the upcoming release, it is good when I spend some time in the store code to get a grasp of where changes are needed.
You are certainly right: My multi-store patch does not properly rebind special variables used by subsystems, and this is something I will add. I want to make sure that there is no "performance overhead" for the single-store case, which makes it slightly more complicated. I'll let you know once I have committed. While fixing the subsystem issues, I will need to repair random state handling which is also broken in the multiple store case.
If you did not see it: Trac generates RSS feeds for the Subversion log, which is why I have stopped distributing commit notifications by email. http://bknr.net/trac/timeline?milestone=on&ticket=on&changeset=on&am... the full feed.
-Hans