User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:63.0) Gecko/20100101 Firefox/63.0 Build ID: 20180815100249 Steps to reproduce: Related with https://www.reddit.com/r/firefox/comments/92j1ob/mediumcoms_undoredo_is_not_working_on_ff_nightly/ , * Create a new story on Medium.com using FF Nightly * Make some changes like add inline code blocks or few words * test undo/ redo functionality via key board shortcuts Actual results: Undo/ redo works only for last word change, sometimes totally not working as well. Expected results: undo/ redo functionality should work on nightly

This is due to Bug 1440189. Flipping the dom.keyboardevent.keypress.dispatch_non_printable_keys_only_system_group_in_content pref or adding `medium.com/p/` to the dom.keyboardevent.keypress.hack.dispatch_non_printable_keys pref works around the issue.

cc'ing astevenson, in case we have some contacts at Medium and they can fix it on their side like we did with GDocs?

https://help.medium.com/hc/requests/213276 for reference

I don't have a contact at Medium unfortunately, but have sent a message to Medium support as well.

Was contacted back by a Medium engineer today, provided the details of this report.

Just in case, we have a site compat doc for this issue: https://www.fxsitecompat.com/en-CA/docs/2018/non-printable-keys-will-soon-stop-firing-keypress-event/

Thanks Kohei, I actually shared that link with them already. :)

Hi Adam, any update from Medium folks?

Still having same issue btw

They are looking into the issue and have been active in communicating back with us. Will update when I have more info to share.

:kohei, can we close this now that Bug 1440189 is fixed? It doesn't reproduce on Nightly any longer at least.

No, it’s a regression introduced by Bug 1440189. I can still produce the issue. If it takes time for Medium to fix the issue, we have to add an exception like Etherpad and others. Otherwise, this bug should fall under Tech Evangelism.

As Kohei informed, this is still reproducible in Nightly and I faced this issue at least for 2 months in Nightly now. It's so grateful if Mozilla can fix this from browser side. Thanks

According to comment #2 and comment #13, could you take a look? Thank you so much.

This needs to be fixed from the Medium end. Bug 1440189 simply brings Gecko into line with the spec and other engines. We are not shipping it to release, however, until major Web compat issues such as this are resolved.

Yes, this needs to be fixed by Medium. On the other hand, we should add medium.com into the blacklist for avoiding inconvenience of Nightly testers (I thought that they'd fix the bug quickly).

I landed the patch for bug 1495627 to disable the new behavior only under "medium.com/p/". Therefore, staff of Medium will be not able to reproduce this bug with tomorrow's Nightly and newer. So, could you let them know that they need to remove ",medium.com/p/" from "dom.keyboardevent.keypress.hack.dispatch_non_printable_keys" in about:config.

Thanks Masayuki! Will let them know.

Thanks for everyone for checking this and adding a patch from Nightly side. undo/ redo functionalities are now working perfectly on Nightly.

Looks like that undo/redo work fine with Nightly even if medium.com is removed from the blacklist. Did you get some replay from them?

I know they were working on a patch, but hadn't heard back. Just pinged them again. Thanks for the follow up. :)

They've confirmed that they fixed this issue. Closing this report as Fixed.

Thanks, I'll remove medium.com from the blacklist.