title: react-leaflet map not correctly displayed
body: <p>I'm trying to use <code>react-leaflet</code> to display a map. I use the code from <a href="https://jsfiddle.net/paul_lecam/q2v7t59h/" rel="noreferrer">this fiddle</a> which is working, but on my computer I have this output</p>
  
  <p><a href="https://i.stack.imgur.com/rw2xG.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/rw2xG.jpg" alt="enter image description here"></a></p>
  
  <p>Here is my code :</p>
  
  <p><strong>DeviceMap.js</strong></p>
  
  <pre><code>import React from 'react'
  import { Map, Marker, Popup, TileLayer } from 'react-leaflet';
  
  export class DeviceMap extends React.Component {
    constructor() {
      super();
      this.state = {
        lat: 51.505,
        lng: -0.09,
        zoom: 13,
      };
    }
  
    render() {
      const position = [this.state.lat, this.state.lng];
      return (
        &lt;Map center={position} zoom={this.state.zoom} scrollWheelZoom={false}&gt;
          &lt;TileLayer
            attribution='&amp;copy; &lt;a href="http://osm.org/copyright"&gt;OpenStreetMap&lt;/a&gt; contributors'
            url='http://{s}.tile.osm.org/{z}/{x}/{y}.png'
          /&gt;
          &lt;Marker position={position}&gt;
            &lt;Popup&gt;
              &lt;span&gt;A pretty CSS3 popup. &lt;br/&gt; Easily customizable.&lt;/span&gt;
            &lt;/Popup&gt;
          &lt;/Marker&gt;
        &lt;/Map&gt;
      );
    }
  }
  
  export default DeviceMap
  </code></pre>
  
  <p><strong>DeviceTabs.js</strong></p>
  
  <pre><code>export class DeviceTabs extends React.Component {
    state = {
      index: 0
    };
  
    handleTabChange = (index) =&gt; {
      this.setState({ index })
    };
  
    render () {
      return (
        &lt;Tabs index={this.state.index} onChange={this.handleTabChange}&gt;
          &lt;Tab label='Values'&gt;
            &lt;DeviceTable {...this.props} /&gt;
          &lt;/Tab&gt;
          &lt;Tab label='Map'&gt;
            &lt;div className={style.leaflet}&gt;
              &lt;DeviceMap /&gt;
            &lt;/div&gt;
          &lt;/Tab&gt;
        &lt;/Tabs&gt;
      )
    }
  }
  </code></pre>
  
  <p><strong>style.scss</strong></p>
  
  <pre><code>.leaflet {
    height: 300px;
    width: 100%;
  }
  </code></pre>
  
  <p>There is no error in the console, and I have no more idea where to search. Since the fiddle is working it is not a bug. Did I miss something ?</p>