[Note]: - I managed to reproduce this issue only on some sites like https://twitter.com/, http://www.imdb.com/, https://www.amazon.com/ and https://soundcloud.com/. [Affected versions]: - Latest Aurora 51.0a2 (2016-10-17) - Latest Nightly 52.0a1 (2016-10-16) [Affected platforms]: - Windows 10 x64 - Windows 7 x86 - Ubuntu 16.04 x64 - Mac 10.11.6 [Steps to reproduce]: 1. Launch Firefox 2. Go to one of above mentioned pages (e.g. http://www.imdb.com/) 3. Open the same page in a new tab 4. On the first tab, open the Menu [≡] and click the [+] Zoom In Control button until 120% zoom level is reached 5. Go to the second tab - inspect the Zoom indicator - inspect the [%] Zoom Level displayed in Menu Panel 6. Repeat step 4 and step 5 for another zoom level values [Expected result]: - Zoom indicator always displays the same zoom level for the same sites (open in different tabs) - Both Zoom indicator and Menu Panel are accurately reflecting the chosen zoom levels [Actual result]: - Zoom indicator doesn't always update on tab switching for the same site [Regression range]: - This issue is not a regression, as the issue is reproducible on 51.0a1 (2016-08-16), when bug 565718 was fixed [Additional notes]: - This issue is not always reproducible on the first try

Track 51+ as this feature will be shipped in 51. Hi :jaws, May I know if you have any updates?

Katie, are you able to take a look at this?

Sure!

Does this still affect 53? Seems likely.

I found I was able to reproduce this issue, though it is intermittent as Iulia mentioned. The trick is to quickly change tabs after increasing the zoom in the widgets menu panel. This is reproducible for other websites I tried and not limited to the sites suggested in the user story. I believe what is happening is that the "browser-fullZoom:location-change" observer is sent before the "browser-fullZoom:zoomChange" observer has finished updating the window's zoom level, and so the window reference for the "browser-fullZoom:location-change" still has the older zoom level cached in it. If you switch between browsers, the zoom level in the URL bar button updates with next "browser-fullZoom:location-change" observer notification. I won't be able to troubleshoot this issue further since I'm starting a new job soon, but let me know if you have any questions on this!

Too late for 51. Mark 51 won't fix.

Jared, who is in charge for the zoom indicator?

I guess it would be Gijs or myself. I am waiting on a needinfo reply at https://bugzilla.mozilla.org/show_bug.cgi?id=1300376#c25 to land a simple patch that may fix this issue.

Mass wontfix for bugs affecting firefox 52.

Is this still relevant, since the bug in comment 8 is fixed?

I believe this is fixed. Iulia, can you still reproduce it?

Based on comment 8 and https://bugzilla.mozilla.org/show_bug.cgi?id=1300376#c36, Firefox 53 is fixed.

I also can confirm that the issue is not reproducible anymore on 53.0.3 build1 (20170518000419) across platforms (Windows 10 x64, Ubuntu 16.04 x64 and macOS 10.13.2). 60.0a1 (2018-02-04) and 59.0b6 build1 (20180201171410) are not affected.