title: dxBarManager - icon not displaying on dxBarLargeButton1
body: <p>I am using dxBarManager1. To it, I assigned cxImageList1.
  I added an icon of appropriate size in cxImageList1 and tried (on formshow):</p>
  
  <blockquote>
    <p>dxBarLargeButton1.LargeImageIndex := 0;</p>
  </blockquote>
  
  <p>But it will not show.
  Why ?</p>
  
  <p>The code is simple :</p>
  
  <pre><code>unit Unit3;
  
  interface
  
  uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ImgList, cxGraphics, dxBar,
    cxClasses;
  
  type
    TForm3 = class(TForm)
      dxBarManager1: TdxBarManager;
      dxBarManager1Bar1: TdxBar;
      dxBarLargeButton1: TdxBarLargeButton;
      cxImageList1: TcxImageList;
      procedure FormShow(Sender: TObject);
    private
      { Private declarations }
    public
      { Public declarations }
    end;
  
  var
    Form3: TForm3;
  
  implementation
  
  {$R *.dfm}
  
  procedure TForm3.FormShow(Sender: TObject);
  begin
  dxBarLargeButton1.LargeImageIndex := 0;
  end;
  
  end.
  </code></pre>