Question

I have two connected sortable lists. I don’t want the user to be able to leave a list empty. They must have at least one item in the list at all times.

I was trying to do something a long the lines of:

    $( "#unused, #used" ).sortable( {
        connectWith: ".connectedSortable", 
        placeholder: "placeholder",
        items: "li:not(:only-child)"
        }).disableSelection();

Anyone know how to do this?

Answer 1

Use the cancel option instead of items:

$( "#unused, #used" ).sortable( {
    connectWith: ".connectedSortable", 
    placeholder: "placeholder",
    cancel: "li:only-child"
});

This option will prevent sorting when only one item left in the sortable list.

See a working example here.