Hi Corydon

Thanks for reaching out! It looks like you may have an extra end tag that is confusing the compiler. Could you try deleting the last 'end' line in your markup and see if that clears up the issue? Hope this helps!

Thank you @clara h. I came looking for the same reason found your solution and solved my problem.  

Hi Dana so glad this thread was helpful! Please let me know if there's anything else we can do to support your work. 

@micah b101 There is actually.  Your UML for sequence diagrams supports parallel flows but it's of limited use because it's not easy to distinguish the two flows.  I would have expected a syntax more like Alt which is

"par Background actions

  <stuff>

else Foreground actions

  <stuff>

end"

The current syntax does not support 'else' for 'par'.

Is that something that could be added?

Hi Dana thanks for the question! We are grateful for any feedback around your experience using Lucidchart's UML tool and love to know what would make it more useful for you. I've logged this feature request for review by our development team. If you're willing to share further details about your use case and how you'd hope to use a feature like this the development team would love to learn more via our Product Feedback section. Ideas submitted here are considered when prioritizing improvements to Lucidchart. 

I've also surfaced this question internally to investigate any alternative syntax or solutions here which I'll be sure to share with you if available. Thanks again for your request and apologies for any inconvenience. Please let me know if there's anything else I can answer for you!