text: Title: dash_table.DataTable. When  fixed_rows={'headers': True, 'data': 0}, the table gets distorted
  Body: When fixed_rows is set to headers = True the page does not resize and is by default distorted (see image on the right with False value compared with the image on the left with True). I use latest version of dash, dash 1.16.2
  ![Screenshot from 2020-09-28 22-28-15](https://user-images.githubusercontent.com/26002644/94477162-2f1f2280-01da-11eb-8cc8-820b15106e3d.png)
  
  
  `app.layout = html.Div([
      dash_table.DataTable(
          id='datatable-interactivity',
          columns=[
              {"name": i, "id": i, "deletable": True, "selectable": True} for i in df.columns
          ],
          data=df.to_dict('records'),
          editable=False,
          hidden_columns=False,
          filter_action="native",
          sort_action="native",
          sort_mode="multi",
          column_selectable="multi",
          row_selectable=False,
          row_deletable=False,
          selected_columns=[],
          selected_rows=[],
          page_action="native",
          page_current=0,
          fixed_rows={'headers': True, 'data': 0},`