Hello Joffm and thanks for your reply.
That's how that should work.

So, in the end that doesn't work only when my survey is activated.
Hope someone can help me.

Thanks.

The survey works as expected for me - both deactivated and activated. All I can suggest is updating LimeSurvey.

Hello tpartner,
i should be at the latest release for version 2. If i upgrade to version 3 i will have problems with plugins and themes. Or you are telling me to backup and reinstall latest v2 ?

Thanks,

Hello,
what if we inserted participants via MySQL query? Would it be a problem?
The weird thing is that it just doesn't work when activated.

thanks,

OK, we did a fresh new install and checked step by step. The problem was a plugin. I will spend the rest of the night fighting against it. THanks for your support.

Phew!

Which plugin?

It's a custom plugin which forces the processing of relevance equation of all survey groups.