title: Glyph not displayed on datagridview
body: <p>I have a datagridview with some programmaticly sortable columns, the sorting itself is done on mouse click.  I can get the gliph direction property but no glyph is displayed.</p>
  
  <p>Any idea why?</p>
  
  <pre><code>private void gvRules_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
  {
    var column = gvRules.Columns[e.ColumnIndex];
  
    var sortGlyphDirection = column.HeaderCell.SortGlyphDirection;
  
    if (column.SortMode != DataGridViewColumnSortMode.Programmatic)
      return;
  
    switch (sortGlyphDirection)
    {
      case System.Windows.Forms.SortOrder.None:
      case System.Windows.Forms.SortOrder.Ascending:
        gvRules.Sort(column, ListSortDirection.Ascending);
        break;
      case System.Windows.Forms.SortOrder.Descending:
        gvRules.Sort(column, ListSortDirection.Descending);
        break;
      default:
        break;
    }
  }
  </code></pre>