Highcharts - height bug

by sectioni

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>


<div id="mainDiv">

  <div id="menu">test</div>
  <div id="container"></div>
</div>

CSS

html, body {
  height: 100%;
  margin:0;
  padding:0;
}

#mainDiv {
  display:flex;
  flex-direction:column;
  height: 100%;
}

#menu {
  height: 20px;
  background-color:green;
}

#container {
  flex:1;  
  border: 4px solid red;  
}

JavaScript

Highcharts.chart('container', {

    chart: {
        margin: 0,
        spacing:0        
    },

    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
            'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },
    series: [{
        data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4],
        type: 'column'
    }]

});