I found a bug in the jobGroupName-select tag. It added the selected attribute on each option that was not selected, instead of the one that should have been selected.
Hence we ended up with this HTML-ouput.
In my case, the option Top Priority should have been choosen, instead Slow and steady was shown. When I looked at my current saved configuration for this specific job, I saw that Top Priority was saved, so it works correctly, it just shows the wrong jobGroupName.