C# - Blauer Rahmen um deaktivierte MenuItems entfernen

/// <summary>
/// Custom color class to overwrite the professional color table
/// and "disable" the border around disabled menu items.
/// </summary>
public class WhidbeyColorTable : ProfessionalColorTable
{
  /// <summary>
  /// Overwrite the MenuItemBorder property to
  /// disable the border around disabled items.
  /// </summary>
  public override Color MenuItemBorder
  {
    get
    {
      return Color.Transparent;
    }
  }
}

// --------------------
// Initializing...
// --------------------

// Create a new instance of the custom color table
ProfessionalColorTable whidbeyColorTable = new WhidbeyColorTable();

// Enable system colors to a "whidbey" look and feel
whidbeyColorTable.UseSystemColors = true;

// Now render the main menu strip using the new colored render
menuStrip.Renderer = new ToolStripProfessionalRenderer(whidbeyColorTable);