Вопрос решился вот так:
drop: function (e, ui) {
if (ui.draggable[0].id == "auth") {
var $field = '<div class="input-block"><span class="label label-primary">'+ ui.draggable.text() +'</span><input type="text" class="form-control main-input" placeholder="Your text"></div>';
var $el = $($field);
$el.append($('<div class="removeqwe"><button type="button" class="btn btn-default btn-xs remove"><span class="glyphicon glyphicon-trash"></span></button></div>').click(function () { $(this).parent().detach(); }));
$(this).append($el);
}
else if (ui.draggable[0].id == "second") {
....
}
else if (ui.draggable[0].id == "third") {
....
}
else if (ui.draggable[0].id == "fourth") {
....
}
}
