Ok, I know why it happens, but I don't know how to fix it.  I've got
code that responds to a user clicking an up or down arrow button which
moves a div layer down or up into a placeholder div layer.  That all
works fine, but when the user moves a part up or down, then causes a
postback, I get the viewstate problem.

Failed to load viewstate. The control tree into which viewstate is
being loaded must match the control tree that was used to save
viewstate during the previous request. For example, when adding
controls dynamically, the controls added during a post-back must match
the type and position of the controls added during the initial
request.

How can I take a div and have it switch places and not break
viewstate?
If you want code, let me know-