Dear Richard,
thanks for elaborating on your ideas. As I am still figuring out what works best, I'll give them a try. Especially the approach to let the source deal with passing the arguments to the block - though this requires more changes. The problem is NOT, as some commentators apparently think, that you are using a block. Indeed. A block provided (by the user) is actual the natural way in my case. The problem is that having thought of one way to wire things up -- not an unreasonable way, in fact -- you concentrated on making *that* way faster instead of looking for other ways to do it. You're right. I first wanted to see how far I can get with this "direct" approach before trying other techniques. :-D All the best! Steffen
