title: material-ui Select Box not showing selection
body: <p>I have a material-ui select box that is populated with a state variable. No matter what I have tried, I cannot get the value to actually show when I select an option. Can anyone tell me why? It keeps just giving me a blank bar. I even took an example from another code sandbox and copied it almost exactly. One thing I did notice is that my event.target.value is always undefined, and I am not sure why. So I just use value, instead, in my handleChange function. Any help is greatly appreciated! This has been driving me crazy. </p>
  
  <p>Code Sandbox: <a href="https://codesandbox.io/s/jnyq16279v" rel="noreferrer">https://codesandbox.io/s/jnyq16279v</a></p>
  
  <p>Code:</p>
  
  <pre><code>import React from 'react';
  import MenuItem from 'material-ui/MenuItem';
  import Select from 'material-ui/SelectField';
  import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
  
  export default class KKSelect extends React.Component {
  
      constructor(props) {
          super(props);
          this.state = {
              selectOptions: [
                  {
                      value: "Image",
                      id: "1"
                  },
                  {
                      value: "Integer",
                      id: "2"
                  },
                  {
                      value: "Decimal",
                      id: "3"
                  },
                  {
                      value: "Boolean",
                      id: "4"
                  },
                  {
                      value: "Text",
                      id: "5"
                  }
              ],
              selectedValue: ""
          };
      }
  
      renderSelectOptions = () =&gt; {
          return this.state.selectOptions.map((dt, i) =&gt; {
              return (
                  &lt;MenuItem key={i} value={dt.id}&gt;
                      {dt.value}
                  &lt;/MenuItem&gt;
              );
          });
      }
  
      handleChange = (event, value) =&gt; {
          this.setState({ selectedValue: value });
      };
  
      render() {
          return (
              &lt;MuiThemeProvider&gt;
  
                  &lt;Select
                      value={this.state.selectedValue}
                      onChange={this.handleChange}
                  &gt;
                      {this.renderSelectOptions()}
                  &lt;/Select&gt;
  
              &lt;/MuiThemeProvider&gt;
          );
      }
  }
  </code></pre>