The logs
```
  Stack:
    Error: Protocol error (Target.createTarget): can't access property "closing", selectedTab is null _setPositionalAttributes@chrome://browser/content/tabbrowser-tabs.js:1123:11
    _insertTabAtIndex@chrome://browser/content/tabbrowser.js:3286:25
    addTab@chrome://browser/content/tabbrowser.js:2710:16
    addTab@chrome://remote/content/shared/TabManager.jsm:24:31
    createTarget@chrome://remote/content/cdp/domains/parent/Target.jsm:90:28
    execute@chrome://remote/content/cdp/domains/DomainCache.jsm:101:25
    execute@chrome://remote/content/cdp/sessions/Session.jsm:64:25
    onPacket@chrome://remote/content/cdp/CDPConnection.jsm:248:36
    onMessage@chrome://remote/content/server/WebSocketTransport.jsm:89:18
    handleEvent@chrome://remote/content/server/WebSocketTransport.jsm:71:14
    openPromptSync@resource://gre/modules/Prompter.jsm:1057:17
    alert@resource://gre/modules/Prompter.jsm:1329:17
    alert@resource://gre/modules/Prompter.jsm:80:7
    _displayPrintingError@chrome://global/content/printUtils.js:572:21
```
My feeling is that something is wrong with the printing test and an alert is generated which blocks following attempts to get the current selected tab (see https://searchfox.org/mozilla-central/source/toolkit/components/printing/content/printUtils.js#572).
["#\\39 3R", "Check5=Off::12"],
          ];
          for (const [selector, expectedText] of expected) {
            
            await clearInput(page, "#\\38 0R");
            await page.click(selector);
            await page.waitForFunction(
              `document.querySelector("#\\\\38 0R").value !== ""`
            );
            const text = await page.$eval("#\\38 0R", el => el.value);
            expect(text).withContext(`In ${browserName}`).toEqual(expectedText);
          }
        })
      );
    });
    it("must show values in a text input when clicking on checkboxes or radio with no actions", async () => {
      await Promise.all(
        pages.map(async ([browserName, page]) => {
          const expected = [
            ["", "Off;Off"],
            ["#\\39 4R", "Yes;Off"],
            ["#\\39 5R", "Yes;NoAct2"],
            ["#\\39 6R", "Yes;NoAct3"],
            ["#\\39 4R", "Off;NoAct3"],
            ["#\\39 5R", "Off;NoAct2"],
          ];
          for (const [selector, expectedText] of expected) {
            
            await clearInput(page, "#\\38 0R");
            if (selector) {