So everything was going fine, and now I got this error when I go to compile. It won't let me compile. It just pops up with this error.
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So I renamed a panel and it's OK now. Sorry. I guess I has a panel name, actidentily renamed it and got the error. When I changed the name back, the error went away. However, error message is not very helpful.
The error message is indeed confusing. However if you go to the designer script as suggested and run the script then you will see a more accurate error message.