lect)').appearance,'base-select');
  await test_driver.bless('showPicker');
  select1.showPicker();
  assert_false(select1.matches(':open'),'Switching appearance in :popover-open should re-close the picker');
  assert_equals(getComputedStyle(select1,'::picker(select)').backgroundColor,red);
  await new Promise(resolve => requestAnimationFrame(resolve));
  assert_false(select1.matches(':open'),'There should be no oscillation or re-opening the picker');
  await new Promise(resolve => requestAnimationFrame(res