title: Unlock horizontal scrolling of group headers with Tabulator
body: <p>I have a table with grouped headings. The group headings rows have multiple columns that I'd like to scroll with the rest of the table.
  Below is an example table in jsfiddle and the code to produce it:</p>
  
  <p><a href="https://jsfiddle.net/Kieran123/kuocqgr0/1/" rel="nofollow noreferrer">https://jsfiddle.net/Kieran123/kuocqgr0/1/</a></p>
  
  <pre><code>var employeeeTable = new Tabulator("#example-table", {
      height:"311px",
      layout:"fitData",
      movableRows:true,
      groupBy:["gender"],
      columns:[
          {title:"Name", field:"name", width:200},
          {title:"Progress", field:"progress", formatter:"progress", width:200},
          {title:"Gender", field:"gender", width:200},
          {title:"Rating", field:"rating", formatter:"star", align:"center", width:200},
          {title:"Date Of Birth", field:"dob", align:"center", sorter:"date", width:200},
      ],
      data: [
          {id:1, name:"Oli Bob", progress:12, gender:"male", rating:1,  dob:"14/04/1984", car:1},
          {id:2, name:"Mary May", progress:1, gender:"female", rating:2,  dob:"14/05/1982", car:true},
          {id:3, name:"Christine Lobowski", progress:42, gender:"female", rating:0,  dob:"22/05/1982", car:"true"},
          {id:4, name:"Brendon Philips", progress:100, gender:"male", rating:1,  dob:"01/08/1980"},
          {id:5, name:"Margret Marmajuke", progress:16, gender:"female", rating:5,  dob:"31/01/1999"},
          {id:6, name:"Frank Harbours", progress:38, gender:"male", rating:4, dob:"12/05/1966", car:1},
          {id:7, name:"Jamie Newhart", progress:23, gender:"male", rating:3, dob:"14/05/1985", car:true},
      ],
      groupHeader:function(gender, data) {    
          return "&lt;div class=\"tabulator-cell\" style=\"text-align: center; width: 200px;\"&gt;" + gender + "&lt;/div&gt;" + 
                  "&lt;div class=\"tabulator-cell tabulator-cell-average\" style=\"text-align: center; width: 200px;\" &gt;50%&lt;/div&gt;";
      },
  });
  </code></pre>
  
  <p>Below is an example of the current table behaviour, but I'd like the "male|50%" columns to scroll horizontally with the rest of the table, instead of being frozen. Is this possible?</p>
  
  <p><a href="https://i.stack.imgur.com/rJlEr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rJlEr.png" alt="Current behaviour"></a></p>