The Code is the code i was posting above. If you look at the provided screenshots, then you can see, that I get displayed what i want. All functions as a MultiSelectCheckbox Form. The problem that I have had with saving the form still persists, but meanwhile I found an ugly workaround that does the job for the moment. Next thing I was aware of is, that, (with a field max_lengt of 100 per function) somehow Django throws a warning, if you check enough functions to get their combined char length larger than 100. As You said, I myself also have no idea, why. The “workaround” here was to use single items like {{ form.function }} instead of {{ form.as_div }}. Then the warning is not displayed…
edit: The funcionality was not disturbed by the warning, it just looked ugly 