Hello Mat,
Thank you for your reply.
I have installed Healtch Check but I have an error:
You don’t have any of the default themes installed. A default theme helps you determine if your current theme is causing conflicts.
However I have the theme Hotel master activated. I tried to install a standard theme instead but I still see this error. I have the feeling that with this error, Health Check won’t be able to tell me more about my Menu Icon issue.
Thanks a lot!