Select2 - avoiding duplicates tags

[kros]

How can I avoiding duplicates tags in Select2 input?
When I type tag name on the keyboard string is added to input field, but when I select tag from dropdown list (results from the database) the id is added to input (look at console.log on screenshot). So I can select tag from list and add the same tag from keyboard.

Moreover, I need the `text` of tags, not `id` from dropdown list while submit a form.

HTML:

<input type="hidden" id="categories" name="categories" style="width:100%" value="${categories}">

JS:

$("#categories").select2({
tags: true,
tokenSeparators: [","],
placeholder: "Dodaj",
multiple: false,
minimumInputLength: 3,
maximumInputLength: 50,
maximumSelectionSize: 20,
ajax: {
quietMillis: 150,
url: '${request.route_url("select2")}',
dataType: 'json',
data: function (term, page) {
return {
q: term,
page_limit: 10,
page: page,
};
},
results: function (data, page) {
var more = (page * 10) < data.total;
return {results: data.categories, more: more};
}
},
initSelection: function (element, callback) {
var data = [];
$(element.val().split(",")).each(function () {
data.push({id: this, text: this});
});
callback(data);
},
createSearchChoice: function (term) {
return { id: term, text: term };
},
}).change(function (e) {
if (e.added) {
console.log($("#categories").val())
console.log(e)
}
});

Ps I posted this question on Stack Overflow also. Here is a screenshot.

http://stackoverflow.com/questions/20161301/select2-avoiding-duplicates-tags