Boostrap 3.37 correct height

[grisotto]

In the https://github.com/select2/select2-bootstrap-theme/blob/master/dist/select2-bootstrap.css

I needed to change this

.select2-container--bootstrap .select2-selection--single {
  height: 34px;
  line-height: 1.42857143;
  padding: 6px 24px 6px 12px;
  /**
     * Adjust the single Select2's dropdown arrow button appearance.
     */
}

To

.select2-container--bootstrap .select2-selection--single {
  height: 44px;
  line-height: 1.42857143;
  padding: 10px 24px 6px 12px;
  /**
     * Adjust the single Select2's dropdown arrow button appearance.
     */
}

my html code:

<div class="input-group">
           <div class="form-group">
                   <select data-placeholder="Selecione um aluno" class="form-control " id="aluno" >
                               <option>1</option>
                               <option>2</option>
                    </select>
            </div>
            <div class="input-group-btn">
                    <button type="submit" name="save"  value="Salvar"  class="btn btn-success" ><i class="glyphicon glyphicon-plus"></i></button>
             </div>
</div>

[cyberbit]

It appears you are using a Bootstrap theme (Bootswatch or otherwise). This is expected behavior when using themes. You would need to compile the LESS/SCSS into your project to get the styling to behave correctly automatically.

[fk]

Seconding @cyberbit – thanks for helping out – and closing this!