Bootstrap 3 - Select2 don't resize

Is this a bug?
#1

Hi guys, recently I had use Select2 and I noticed some rare behaviour.

When your resize the window the select2 don’t resize with it.

Captura

I did some research and I found out when you remove the iniatilation of the select2 in JS it resize noramally.

HTML:

<div class="row">
                    <div class="col-sm-12">
                        <div class="form-group col-sm-3 has-feedback" id="gproblem">
                            <label class="control-label" for="iunidad_atencion">Problem *</label>
                            <select class="form-control" id="iNproblem" name="problem">
                                <option value="">Seleccione la problem</option>
                            </select>
                        </div>
                        <div class="form-group col-sm-3 has-feedback" id="ganother">
                            <label class="control-label" for="ianother">Another*</label>
                            <select class="form-control" id="iNanother" name="ianother">
                                <option value="">Seleccione la another</option>
                            </select>
                        </div>
                    </div>
                </div>

JS:

$('#iNproblem').select2({
        //
    });

I use Bootstrap 3.