I've seen a lot of posts about this multiple post-back issue, and I wanted to pass along how I was finally able to solve this annoying problem. To do so, I'll have to admit to using some sloppy client side coding, but I'll bare my sloppiness for the benefit of others.
What finally resolved the multiple postbacks for me was settling on a single technique for decorating html elements. I had some div and table elements that contained both html attributes along with some in-line styles, and for each instance where this occurred in the web page, I got an additional postback. When I finally made all decorations CSS, whether inline or via a class attribute, the problem disappeared completely.
That's the whole story.
If anyone would like to comment on _why_ this occurred, I'd enjoy the discussion.
David