User Agent: Mozilla/5.0 (X11; Linux i686; rv:49.0) Gecko/20100101 Firefox/49.0 Build ID: 20160516030211 Steps to reproduce: (My system: Linux 32 bit, GTK3 version 3.4.2, Gnome 3.4.2) With Firefox Aurora or Firefox Central (and e10s enabled): open 2 or more tabs and load different sites. With pages fully loaded, switch between tabs. Actual results: Text in titlebar (and in Firefox taskbar button) doesn't change: stuck on latest loaded tab. Expected results: Switching between tabs text should change accordingly. This happens with Aurora and Central. If I disable e10s, everything works ok.

This works for me on Ubuntu 14.04 with latest Nightly 49.0a1, 20160517030211 Stefano, please try in safemode. If it works in that case, there may be an add-on in play. If so get out of safemode and then post your about:support, thanks.

Yeah, you're right. In safemode it works. So I've tried disabling addons one at a time: the problem is in "Flash Video Downloader - YouTube HD Download [4K]" (version 13.2.1). At this point I think my "about:support" page would be superfluous. If I'm wrong, let me know. Sorry for the "false alarm".

Stefano, excellent, thank you for quickly narrowing it down to the FVD add-on.

Hi Michelle, I'm not sure if i can send to you for test validation. In the spreadsheet of testing for Flash Video Download Helper it says "fail:issues know" and references bug 946594. but i had thought those were resolved based on comment 20. Can i ask the person who tested for specifics on how it failed? and did they notice this tab issue as well?

@Shell; yes, Grover tested that. I will have him reach out to you and test against this bug as well.

Just as a follow-up, Shell and I had a chat on IRC, attached are the results from what she asked to test.

results from Grover: Mac and Windows without shims work (YAY!): the icon turns blue and can download and the Text in titlebar (and in Firefox taskbar button) doesn't change: stuck on latest loaded tab. will requested test on Linux WITHOUT shims 1. Install Flash Video Downloader: https://addons.mozilla.org/en-US/firefox/addon/flash-video-downloader/ 2. Play a YouTube Flash video 3. Click Flash Video Downloader's blue arrow icon to download the YouTube Flash video 4. It works! 5. Play a Vimeo Flash video RESULT: Flash Video Downloader's arrow icon does not turn blue because it can't find the Vimeo Flash video. Also check: Text in titlebar (and in Firefox taskbar button) changes and isn't stuck on latest loaded tab. Previous notes from Grover's tests on Win and Mac: Windows 7 x32/Windows 8.1 x64/Windows 10 x64: Shim & E10s Enabled - Fail Shim Disabled & E10s Enabled - Pass **** (this is green light for scenario we want) Shim Enabled & E10s Disabled - Pass Shim & E10s Disabled - Pass Mac OSX: Shim & E10s Enabled - Pass Shim Disabled & E10s Enabled - Pass **** (this is green light for scenario we want) Shim Enabled & E10s Disabled - Pass Shim & E10s Disabled - Pass

Stefano; is this still an issue for you? I can confirm Nightly channel is working w/o error. Shell; this looks good, Can you suggest a Product/Component where I can place this if further investigation is needed. Version 50.0a1 Build ID 20160722030235 User Agent Mozilla/5.0 (X11; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0 Multiprocess Windows 1/1 (Enabled by user)

Michelle; setting to 'false' (in about:config) 'extensions.interposition.enabled' and 'extensions.interposition.prefetching' (is this the right procedure for disabling shims?) it works, text in titlebar changes accordingly. So: e10s enabled + shims disabled -> OK (about text/tabs switching) BUT: loading a page with flash video, the addon arrow is blue (video detected) but -clicking on it- no dropdown menu for download. If I disable e10s (so: e10s disabled + shims disabled), then the addon works (the dropdown menu for download appears). Tested with Nightly build 20160722030235 - user agent Mozilla/5.0 (X11; Linux i686; rv:50.0) Gecko/20100101 Firefox/50.0. FVD version: 13.2.3.

working win 7 and xp, seeing this issue with ubuntu, mac, and win 10 https://docs.google.com/spreadsheets/d/1AUlHv0b1Pb_UMzLroT-Z5kFDSSReFWmkHHpz4m9dNhs/edit#gid=1989668749

The developer has been contacted.

Developer has been contacted and is working on it.