Select2 : open on focus

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.css">
<input type="text" id="test2" />
<select name="select" id="test">
</select>

CSS

p {
    margin: 1em 0;
}

JavaScript

$('#test').select2({
    data: [{
        id: 0,
        text: "enhancement"
    }, {
        id: 1,
        text: "bug"
    }, {
        id: 2,
        text: "duplicate"
    }, {
        id: 3,
        text: "invalid"
    }, {
        id: 4,
        text: "wontfix"
    }],
    width: "300px"
}).data('select2').listeners['*'].push(function(name, target) { 
	if(name == 'focus') {
		$(this.$element).select2("open");
	}
});