Assistance on LimeSurvey forum and LimeSurvey core development are on my free time.
I'm not a LimeSurvey GmbH member,
professional service on demand
,
plugin development
. I don't answer to private message.
Thank you very much for your help and patience with me.
I finally made it (see attached file).
A small remark, although it is not important for me: the "Help" message is not shown, even if the "Hide tip" button is disabled (Off).
This survey is part of my PhD thesis and I want to send it in September.