Errors when adding FormView to SmartPart with AJAX

When I added a FormView control embedded in an UpdatePanel in a User Control, in a SmartPart with AJAX I got the following error when attempting to switch to Edit mode:
Sys.InvalidOperationException: Could not find UpdatePanel with ID 'ctl00_ctl00_xxxx'. If it is being updated dynamically then it must be inside another UpdatePanel.
I never did find a solution to this problem. But I found that if I cleared out the web parts out of the Web Part zone, then readded the smart part that appears to have fixed the issue.

I did run into other issues when adding multiple AJAX-enabled SmartParts to a Web Part zone, such as the entire zone blanking out other than the one control when switching to Edit Mode. Again, clearing out the controls and re-adding them, seems to resolve these issues, although I fear they'll crop up again...