uses
 CommCtrl;
// 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;