How do I fix a list item to the end?

[ollieairdat]

I have a tab list menu which uses sortable to allow the user to customise the order in which their tabs appear. I want one of these tab items to fix to the end of the list and not allow it to be dragged elsewhere (which I have achieved using 'filter: ...'). I also don't want any other tabs to be allowed to be dragged past this one. Sorry if I've missed this in the repo!

[ivanatreblle]

This will work for first and last item in list:
onMove: function(e) { if(e.related.classList.contains('element-fixed')) { return false; } },