Hi AMO,
We’re the team that makes the OneNote Web Clipper (https://addons.mozilla.org/en-US/firefox/addon/onenote-clipper/). Some of users have switched to Firefox Quantum and discovered a “bug”.
Our log-in flow opens a popup window, listens for a redirect after log-in, grabs the credentials, and then closes the window. After switching to Quantum, the Window no longer closes, and the console shows the error message: “Scripts may not close windows that were not opened by script.”
The documentation is clear here (https://developer.mozilla.org/en-US/docs/Web/API/Window/close) that closing a window via JS that wasn’t opened via JS is not possible. While we are still determining where in our code we are closing this (via JS or JS that exists on the page that ends up being loaded), we still thought we should report it, as this behavior is different than previous versions of Firefox and differs from Chrome as well.