Duplicate empty header occur in datatable when enabling scrollX or scrollY when using Google Chrome

Question

I have a datatable in my program. And I want it to be scrollable horizontally so what I did was like this:

var tableI = $('#table_data').DataTable({
    "bLengthChange": false,
    "scrollX": true,
     "dom": 'frtp'
});

It came out like this(as sample output):

It doubled the header. How am I going to fix this?

EDIT: Here's another sample:

here's my HTML code:

<table class="table table-striped" id="act_data" width="100%">  <div style="float:left;width:385px" >
    <button type="button" id="edit_acc" class="btn btn-primary" data-toggle="modal" data-target="#editAcc"><span class=" fa fa-edit "> Edit Account</span></button>
      <button type="button" id="de_act" class="btn btn-primary" data-toggle="modal" data-target="#DeAcc"><span class=" fa fa-edit "> Activate/Deactivate</span></button>
      <!-- <button type="button" id="refresh" class="btn btn-link"  data-target="#DeAcc"><span class="fa fa-refresh"></span></button>-->
      <a href="<?php echo site_url('admin/homeAdmin/homepage')?>?id=6" class="btn btn-link"><span class="fa fa-refresh"></a>
    </div><thead class="header">
      <tr class="well">
        <th style="font-size: 14px;">Employee ID#</th>
        <th style="font-size: 14px;">Username</th>
        <th style="font-size: 14px;">Account Type</th>
        <th style="font-size: 14px;">Status</th>
      </tr>
    </thead>

    <tbody>
      <?php if($result != NULL){?>
        <?php foreach($result as $row){ ?>
            <tr>
               <td style="font-size: 15px;padding-left: 20px;">
                   <?php echo $row->employeeID;?>
                   <input type="hidden" name="userID" id="userID" value="<?php  echo $row->userID;?>" />
                   <input type="hidden" name="pass" id="pass" value="<?php  echo $row->password;?>" />

              </td>

              <td style="font-size: 15px;padding-left: 20px;">
                   <?php echo $row->username;?>
              </td>
              <td style="font-size: 15px;padding-left: 20px;">
                   <?php echo $row->usertype;?>
              </td>
              <td style="font-size: 15px;padding-left: 20px;">
               <?php echo $row->status; ?>
               </td>

          </tr>
        <?php }?>
      <?php }?>
    </tbody>
  </table> 

Answer 1

I had the same issue with firefox & firefox developer edition. The root cause is, when we set scrollX:true, datatable adds an additional div with a table and a header inside, apart from the table & header already constructed. This is to get the scrolling within table effect.

Datatable, tries to set the height to 0px, to hide it. Some browsers don't interpret this properly.

<tr style="height: 0px;" role="row"> 

To hide it, changing the style to this row to 'hidden' will break the structure of the table. The working solution would be, to have visibility:'collapse'

Sample datatable configuration:

tableElement.DataTable({
    "scrollX": true,
    "initComplete": function(settings, json) {
        $('.dataTables_scrollBody thead tr').css({visibility:'collapse'});
    }
    //other datatable configurations...  
});

since it's a table, we need to have visibility:'collapse' and not visibility:'hidden' - more info on visibility css property