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Your LimeSurvey version: 3.28.54
Own server or LimeSurvey hosting: LimeSurvey Cloud hosting
Survey theme/template: Sea Green
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The question-help ('the question mark followed by some instructions') is by default displayed at the bottom of a question container. I would like to position the question-help in the container between a question and the answer options. 

How can I achieve that? I guess I need to change something in the Javascript, but I do not know where to find it. Thanks a lot!

Hi, no need to use javascript.

You only edit the "question.twig" of your extended theme. 
BTW: "sea green" is an admin theme, not a survey theme. Do you use "bootswatch", "fruity" or "vanilla"?

Here you see the original "question.twig"
 
with the question text container, the container for hints and errors, the container of the answer options and at the bottom the help container.

Move it to your desired place
 

and voilá
 

Joffm

Thanks a lot, this fixed it.