Buttons disappear in use

Hello Andrea, 

Thanks for reaching out! 

Diagnosing an issue that cannot be reproduced consistently is challenging. One thing you can try is to republish your course after importing your slides to a new project file to see if this helps. You'll also want to make sure that you're working locally when making changes to your project file. 

If the issue persists, you can reach out to our support team for additional assistance.