Just as a follow up to that last post
Have it reproducible.
- If I restart the webserver each time (I'm using the dev web server at present) with the chart inside the wizard then I get the error - until I move the chart outside the wizard.
- If I restart the webserver with the chart outside the wizard then it works, then when I move the chart inside the wizard again, then it still works.
(Not sure it's relevant, but in this current app my page contains a user control in which I've placed the wizard inside the last step of which I've placed another custom control inside which I've placed the chart)