add_task(async function newtabPreloaded() { await openPreferencesViaOpenPreferencesAPI("paneHome", {leaveOpen: true}); const {contentDocument: doc, contentWindow} = gBrowser; function dispatchMenuItemCommand(menuItem) { const cmdEvent = doc.createEvent("xulcommandevent"); cmdEvent.initCommandEvent("command", true, true, contentWindow, 0, false, false, false, false, null, 0); menuItem.dispatchEvent(cmdEvent); } const menuHome = doc.querySelector(`#newTabMode menuitem[value="0"]`); const menuBlank = doc.querySelector(`#newTabMode menuitem[value="1"]`); ok(menuHome.selected, "The first item, Home (default), is selected."); ok(gBrowser._isPreloadingEnabled(), "Default Home allows preloading."); dispatchMenuItemCommand(menuBlank); ok(menuBlank.selected, "The second item, Blank, is selected."); ok(!gBrowser._isPreloadingEnabled(), "Non-Home prevents preloading."); dispatchMenuItemCommand(menuHome); ok(menuHome.selected, "The first item, Home, is selected again."); ok(gBrowser._isPreloadingEnabled(), "Default Home allows preloading again."); BrowserTestUtils.removeTab(gBrowser.selectedTab); });