const PAGE = ` `; add_setup(async function () { await SpecialPowers.pushPrefEnv({ set: [["test.wait300msAfterTabSwitch", true]], }); }); add_task(async function () { const url = "data:text/html," + encodeURI(PAGE); await BrowserTestUtils.withNewTab( { gBrowser, url, }, async function (browser) { await SpecialPowers.spawn(browser, [], async function () { ok( content.document .querySelector("option[selected]") .matches(":checked"), "Option should be selected" ); }); let popup = await openSelectPopup("click"); await SpecialPowers.spawn(browser, [], async function () { ok( content.document .querySelector("option[selected]") .matches(":checked"), "Option should still be selected" ); }); popup.hidePopup(); } ); });