Affected versions

• 79.0a1 (2020-07-08)
• 78.0b5
• 78.0.1

Affected platforms

• Windows 10
• Ubuntu 18.04

Steps to reproduce

1. Go to https://janus.conf.meetecho.com/screensharingtest.html
2. Click on the Start button
3. Insert a title and click on the Share your screen button
4. Click on the Pick a window (or Share screen) button from the displayed popoup
5. Select any option from the Widow or Screen to share dropdown
6. Check the checkbox from Disable notifications from Nightly while sharing

Actual result

• “Allow” and “Not Now” are cut off almost entirely

Expected result

• The notification panel is extended, the “Allow” and “Not Now” buttons are not cut off

Regression range

• I’ve restrained the regression range to the following: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=99066bbd1b3a288471f2bf7f59f1c99da42610a1&tochange=51dbdcd6e874c5d466f7a163e43973358e06284d

Additional notes

• The issue is reproducible intermittent, sometimes the checkbox needs to be toggled several times to trigger the issue
• Reproducible with 100% scale
• Severity: S3

Anca, do you think you can get a narrower regression range? This looks fairly serious, but the range is too big to find out anything.

I'm not able to reproduce in Windows 10, in 78.0.2 or the latest Nightly (and not able to reproduce in macOS).

Anca, does it reproduce for you in Nightly, or do we think this was somehow fixed? (if it doesn't maybe the --findfix option of mozregression is easier to work with)

(In reply to Gian-Carlo Pascutto [:gcp] from comment #1)

Anca, do you think you can get a narrower regression range? This looks fairly serious, but the range is too big to find out anything.

• Last good revision: ecc5c853bb770cc3f9acc90d9ed9febe086671a0
• First bad revision: ddce7f4b64d96e68a86d7a519f1828d06e37176d
• Pushlog:
  https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ecc5c853bb770cc3f9acc90d9ed9febe086671a0&tochange=ddce7f4b64d96e68a86d7a519f1828d06e37176d
• Potential regressor: 1604412

I can still reproduce the issue with the latest Nightly on Windows 10; see the about:support content
Note that I couldn't reproduce the issue on other two test machines with Windows 10.

Given the regression range, seems like someone involved in widget sandboxing should investigate first.

Affected platforms
Ubuntu 18.04

Anca, the regressor you identified in comment 3 looks very plausible, but that's a Windows only change. Can you actually reproduce this on Ubuntu, or was that a typo?

If it is indeed reproducible on Ubuntu, can you try to find the regression range on that platform? It might be long-standing race that bug 1604412 made easier to hit on Windows, so if we can find the actual regressor, that could help.

(In reply to Gian-Carlo Pascutto [:gcp] from comment #5)

Anca, the regressor you identified in comment 3 looks very plausible, but that's a Windows only change. Can you actually reproduce this on Ubuntu, or was that a typo?

Hmm, not really sure what happened here.. It sure looks like a mistake from my side... I rechecked the reproducible of the issue on Ubuntu with the latest builds and the one mentioned when submitting the issue and indeed, I am not able to see the described problem. Still reproducible on Windows 10 though, with the latest Nightly build.

I haven't been able to get this issue to reproduce on any of my machines.

:Anca - Is there a way for me to get access to a machine that is able to repro the issue?

Thanks!

(In reply to Chris Martin [:cmartin] from comment #7)

:Anca - Is there a way for me to get access to a machine that is able to repro the issue?

Not sure the implication and politics in place for a remote access. Probably a zoom meeting with screen share is a better option. It looks like something specific to my test machine (as mentioned in comment 3 “Note that I couldn't reproduce the issue on other two test machines with Windows 10”). The issue is reproducible with a clean profile, but not reproducible in safe mode. Let me know what additional info I can provide! Screencast with the issue!