It always corrects itself if I rebuild the solution, but if I leave a form and come back to it later it frequently re-appears.
-Larry
Thanks for posting the designer dll. I installed it but the problem remains. I was on VS SP 1 when the problem started. I'm not sure what Microsoft considers to be a "complex form" but it looks to me like it doesn't take much to reach that level.
On one of them, we can design it, and then if its designer is open when we run the project (debug), it immediately shows that message... but it comes back if we close the designer and re-open the file. The others just quit working, so I dunno.