Iframes are not updated until reload

[fregante]

Probably a minor issue, somewhat related to:

• https://github.com/pixiebrix/pixiebrix-extension/issues/1557

Repro

1. Open https://ephiframe.vercel.app/Outer?iframe=https://extra-ephiframe.vercel.app/Cross-domain-iframe%3Fiframe%3D./nested
2. Add button next to "Docs" in the Outer document
3. Set https://*.vercel.app/* as the site
4. Save

⚠️ At this point the button should appear in every iframed document, but doesn't.

5. Reload the page

✅ The button now appears

6. Make changes to the button
7. Save

⚠️ Changes are still not reflected until a reload.

Demo for steps 6-7

https://github.com/pixiebrix/pixiebrix-extension/assets/1402241/babf1e6a-8506-41bd-91cc-ca4cdc351deb

Questions

What is the current support state for iframes? The dev tools cannot select elements inside iframes, but any pre-existing buttons are loaded.