Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

uses
   CommCtrl;

 // Beispiel: Blendet den Button zum Erzeugen eines neuen Verzeichnisses aus. 
// Example: Hide the "Create New Folder" Button. 

procedure TForm1.OpenPictureDialog1Show(Sender: TObject);
 const
   TB_BTN_NEWFOLDER  = 40962;
 var
    hWndToolbar, wnd: HWND;
    tbInfo: TTBButtonInfoA;
 begin
     tbInfo.cbSize := SizeOf(TTBButtonInfo);
     tbInfo.dwMask := TBIF_STATE;
     tbinfo.fsState := TBSTATE_HIDDEN or TBSTATE_INDETERMINATE;

     hWndToolbar := FindWindowEx(GetParent((Sender as TOpenPictureDialog).Handle), 0,
       'ToolbarWindow32', nil);
     SendMessage(hWndToolbar, TB_SETBUTTONINFO, TB_BTN_NEWFOLDER  ,LParam(@tbinfo));
 end;