Firefox iframe Popup Bug Demo

Compare the behavior between cross-origin and same-origin iframes. Click the buttons to trigger the bug.

Test Setup: Left iframe is from firefox-demo-iframe.fly.dev (cross-origin), right iframe is from firefox-demo.fly.dev (same-origin).
Cross-Origin (firefox-demo-iframe.fly.dev)
Same-Origin (firefox-demo.fly.dev)
Top-Level (no iframe)

This runs directly from the top-level page, not inside any iframe.