title: redux-form-material-ui | SelectField | custom onChange prevents to show chosen value
body: <p>I use <code>redux-form</code> and <code>redux-form-material-ui</code> to create some simple form. Values in <code>subdepartment</code> select depend on value chosen in <code>department</code> select. So I created a callback function triggered onChange of <code>department</code> select. Getting data for <code>subdepartment</code> select works, but the value chosen <code>department</code> select does not appear anymore.</p>
  
  <pre><code>import React from 'react';
  import { Field } from 'redux-form';
  import { SelectField } from 'redux-form-material-ui';
  import MenuItem from 'material-ui/MenuItem';
  
  &lt;Field
    name={name}
    component={SelectField}
    hintText={label}
    floatingLabelText={label}
    onChange={callback}
  &gt;
    {this.renderOptions(options)}
  &lt;/Field&gt;
  </code></pre>
  
  <p>The callback:</p>
  
  <pre><code>searchSubdepartments: departmentId =&gt; dispatch(searchSubdepartments(departmentId))
  </code></pre>