Tor Browser issueshttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues2022-01-11T19:33:57Zhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/3875TBB's Firefox should use optimistic data socks handshake variant2022-01-11T19:33:57ZRoger DingledineTBB's Firefox should use optimistic data socks handshake variantTor Proposal 181 lets the Tor client save a round-trip if the application speaks socks in a special way. In short, the application needs to send its data before hearing that the socks connection was successful. It's supported as of Tor 0...Tor Proposal 181 lets the Tor client save a round-trip if the application speaks socks in a special way. In short, the application needs to send its data before hearing that the socks connection was successful. It's supported as of Tor 0.2.3.3-alpha.
Ian originally had suggested to hack polipo to use a modified socks handshake. With polipo out of the picture for TBB, we should make Firefox itself do it.
Is this something Torbutton should (could) do, or should we patch the Firefox we include in TBB?TorBrowserBundle 2.3.x-stableMike PerryMike Perryhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41424Reduce disk activity by disabling some unnecessary tasks and telemetry2023-11-14T22:30:29Zcypherpunks1Reduce disk activity by disabling some unnecessary tasks and telemetryActivity stream needs to be disabled again. Telemetry tasks that cause disk activity should ideally be conditional. `toolkit.telemetry.enabled` is true on nightly builds, that should be locked to false to keep it consistent across all bu...Activity stream needs to be disabled again. Telemetry tasks that cause disk activity should ideally be conditional. `toolkit.telemetry.enabled` is true on nightly builds, that should be locked to false to keep it consistent across all builds. `webextensions.storage.sync.enabled` could be set to false to eliminate 3 files from the profile folder. These will reduce the noise while monitoring files and preferences and could improve the stability and performance of the browser.
~~https://gitlab.torproject.org/tpo/applications/tor-browser/-/commit/bd5c511fdb39f93fb614c2e16fcf3bfa4208c875 disables [LaterRun](https://gitlab.torproject.org/tpo/applications/tor-browser/-/commit/83c9f8b8b9b58b9a01a4111aa830aa544b46b7f2) which stores the profile creation time in `browser.laterrun.bookkeeping.profileCreationTime` and the number of times the browser has been opened since then in `browser.laterrun.bookkeeping.sessionCount`.~~Sponsor 131 - Phase 5 - Ongoing Maintenancecypherpunks1cypherpunks1https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41399Update Mozilla's patch for Bug 1675054 to enable brotli encoding for HTTP oni...2023-10-19T12:48:42ZrichardUpdate Mozilla's patch for Bug 1675054 to enable brotli encoding for HTTP onions as wellSee https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41141#note_2847944
>>>
I think we they also be checking for .onion here ( similar to mixed content blocker https://searchfox.org/mozilla-central/source/dom/security...See https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41141#note_2847944
>>>
I think we they also be checking for .onion here ( similar to mixed content blocker https://searchfox.org/mozilla-central/source/dom/security/nsMixedContentBlocker.cpp#263 ). The mozilla patch( https://hg.mozilla.org/mozilla-central/rev/fc09cf8d7c91 ) just enables brotli encoding for loopback/localhost domains in addition to HTTPS, not for all secure contexts (so http .onion is missing out)
>>>
@tom please let me know if I'm misunderstanding the referenced patch
We should uplift any fix fro this.https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41348cherry-pick macOS OSSpinLock replacements2022-10-19T07:32:24Zrichardcherry-pick macOS OSSpinLock replacementsThis popped up todaY: https://hacks.mozilla.org/2022/10/improving-firefox-responsiveness-on-macos/
These patches landed in Firefox 103:
- [Bug 1670885: Replace deprecated OSSpinLock with os_unfair_lock](https://bugzilla.mozilla.org/sho...This popped up todaY: https://hacks.mozilla.org/2022/10/improving-firefox-responsiveness-on-macos/
These patches landed in Firefox 103:
- [Bug 1670885: Replace deprecated OSSpinLock with os_unfair_lock](https://bugzilla.mozilla.org/show_bug.cgi?id=1670885)
- **f56fb96281556e7eded0cbb884acf1531eb2049d** : Fix post-fork() handlers for PHC/LogAlloc to work on macOS using unfair locks
- **8f9904bb767433e84255b3bc2324d9aadcce3dc2** : Replace deprecated NSSpinLocks with os_unfair_locks in the memory allocator
- [Bug 1774458: Use undocumented, non-public adaptive spinlocks on macOS 10.15+, revert to user-space spinlocks on older versions](https://bugzilla.mozilla.org/show_bug.cgi?id=1774458)
- **7e8fda1a8bf1a7989a6f44735ff3c3a3d1a8bc46** : Use undocumented, non-public adaptive spinlocks on macOS 10.15+, revert to user-space spinlocks on older versions
and this in 106:
- [Bug 1784018: Remove deprecated OSSpinLocks](https://bugzilla.mozilla.org/show_bug.cgi?id=1784018)
- **44cbaf42485d18dad8864addef719c8f3707ad3f** : Remove deprecated OSSpinLocks
We should see if these apply cleanly and consider cherry-picking to alpha (esr102)Sponsor 131 - Phase 3 - Major ESR 102 Migrationrichardrichardhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/33046Test ETP enabled in Tor Browser2020-06-27T14:32:06ZMatthew FinkelTest ETP enabled in Tor BrowserLast year I ran some experiments comparing the loading of pages with Enhanced Tracking Protection (ETP) disabled and then with it enabled. The results from these experiments were not statistically significant, but the preliminary results...Last year I ran some experiments comparing the loading of pages with Enhanced Tracking Protection (ETP) disabled and then with it enabled. The results from these experiments were not statistically significant, but the preliminary results showed that ETP noticeably reduces the best and average case timing, but the variance is still problematic.
On the bright side, this is a good starting point. From an email I sent:
```
I started measuring Tor Browser's
speed while loading various webpages. This was with the goal of
comparing Tor Browser with the measurements Mozilla made two years ago
[0] when they released Quantum (and compared Firefox and Chrome). It
uses benchmarks provided by Firefox's Javascript API (using the
Navigation Timing API).
It seems like Tracking Protection does has a noticable impact on
page-load time. I still have the feeling that investigating ad and
tracker blockers is a worthwhile initiative (especially if we want to
remain relevant). There are some interesting results that require
further analysis because I can't explain them right now.
In the future, it would be very helpful if we extended these
measurements by including tor controller events related to circuit
build and stream sentconnect/connected events. We should also run these
tests from different geographic areas (particularly locations with low
throughput connections).
My takeaway from this is if (ideally) pages should load with 6 seconds
(as was Mozilla's target [0]), then I believe this is achievable as the
other network improvements (correcting weighting, solving bottlenecks,
etc.) are rolled out. In addition, as usual, this will require some
advocacy for helping promote tor-friendly websites.
----
Mozilla's measurements used Selenium for automating the tests. Luckily,
Kushal already made a Tor Browser Selenium driver[1], so adapting
Mozilla's test[2] was relatively simple.
These measurements used a slightly non-standard Tor Browser
configuration. The Navigation Timing API is a fingerprinting vector, so
it is disabled by default. |privacy.resistFingerprinting| was disabled
for these tests. Similarly, NoScript's XSS protection required manual
input while pages loaded, so the XSS protection was disabled for these
tests.
Two sets of tests were run. The first test did not change any other Tor
Browser settings. The second test enabled Tracking Protection. Each test
loaded 20 webpages[3] (19 webpages in that file plus
http://newsweek.com/). The list of webpages is shuffled before each run,
and Tor Browser is restarted between each run.
[0]
https://hacks.mozilla.org/2017/11/comparing-browser-page-load-time-an-introduction-to-methodology/
[1] https://github.com/webfp/tor-browser-selenium
[2] https://github.com/onkeltom/browser_pageloadspeed
[3]
https://github.com/onkeltom/browser_pageloadspeed/blob/master/news.txt
[4] https://w3c.github.io/navigation-timing/#processing-model
```
legacy/trac#30939 is a consequence of this work.
I described in another email how the tests were run:
```
I pushed a branch page_load_timing on
https://github.com/sysrqb/tor-browser-selenium/
It requires the same setup configuration as described in the README. I
installed the dependencies with --user.
- pip install --user tbselenium
- pip install --user -r tor-browser-selenium/requirements-dev.txt
- Downloaded geckodriver from the Github repo
I didn't use xvfb (simply for convenience), so I ran the page-load test
directly with:
$ NO_XVFB=1 TBB_PATH=~/tor-browser_en-US/ py.test tor-browser-selenium/tbselenium/test/test_pageload.py
Change TBB_PATH and path/to/test_pageload.py, as needed. Don't be
surprised if the browser doesn't launch immediately (it take 5-10
seconds on slower computers).
And, in case you're not aware, tor-browser-selenium currently only works
on Linux (the README says Debian/Ubuntu and I successfully used it on
Fedora). You'll need a system tor installed, too (or at least an
instance of tor running already listening on port 9050). I'd like to add
support for letting Tor Browser bootstrap and control its own tor in the
future.
```
See legacy/trac#32976 for a better way we get geckodriver.https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/31893Measure performance of update pings and update downloads in Tor Browser2022-07-08T18:04:41ZGeorg KoppenMeasure performance of update pings and update downloads in Tor BrowserTo get a better understanding of how Tor impacts speed of browsers we could start with measurements for update pings and update downloads in Tor Browser.
Apart from being a good idea in general it would help coming up with actual number...To get a better understanding of how Tor impacts speed of browsers we could start with measurements for update pings and update downloads in Tor Browser.
Apart from being a good idea in general it would help coming up with actual numbers for Mozilla's decision on how to integrate and use Tor in Firefoxhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/31110Tor Browser is having sex with CPU on Safest security level2020-06-27T14:33:13ZcypherpunksTor Browser is having sex with CPU on Safest security levelWhen you're looking at https://github.com/sisbell/tor-android-service/commit/1513f8d2ccaf99fa9d7e8fe1ae00b1f535697030When you're looking at https://github.com/sisbell/tor-android-service/commit/1513f8d2ccaf99fa9d7e8fe1ae00b1f535697030https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/27614Check TCP FastOpen for potential proxy bypass2021-03-23T21:18:03ZGeorg KoppenCheck TCP FastOpen for potential proxy bypassIn https://bugzilla.mozilla.org/show_bug.cgi?id=1188435 (and child bugs) support for TCP FastOpen got implemented. It got disabled on the release track in https://bugzilla.mozilla.org/show_bug.cgi?id=1431738. We should double-check wheth...In https://bugzilla.mozilla.org/show_bug.cgi?id=1188435 (and child bugs) support for TCP FastOpen got implemented. It got disabled on the release track in https://bugzilla.mozilla.org/show_bug.cgi?id=1431738. We should double-check whether we find any proxy bypass issues once this gets enabled.Tor Browser: 10.0https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/27476Remove gap between Tor Launcher window and main browser window2022-01-13T17:21:21ZArthur EdelsteinRemove gap between Tor Launcher window and main browser windowRight now, the Tor Launcher runs, and takes seconds or minutes to complete. The Tor Launcher window, though it says "Tor Browser" on the first screen is not recognizably a web browser, which may be confusing or scary to first-time users....Right now, the Tor Launcher runs, and takes seconds or minutes to complete. The Tor Launcher window, though it says "Tor Browser" on the first screen is not recognizably a web browser, which may be confusing or scary to first-time users.
Then the Tor Launcher window disappears, and then, before a browser window appears, there is a gap of varying length where no window is visible at all. On slow computers, this gap can be as much as tens of seconds and during that time there is no easy way to tell that Tor Browser is still running.
Often users, mistakenly guessing that Tor Browser has crashed, will double-click the Tor Browser app icon a second time and get messages like "Tor Browser is already running, but is not responding" or "Tor unexpectedly exited".
How can we solve this problem? I can think of a few possible solutions:
1. Don't hide the Tor Launcher window until the main browser window is visible. (Build the browser window hidden during the launch process so that it can appear fast as soon as the launch process is done.)
2. Show the main browser window below the Tor Launcher window while it launching process is running. Keep the Tor Launcher window modal (always on top) until it is finished.
3. Embed the Tor Launcher UI in the main browser window. Allow the user to enter a URL in the URL bar even before Tor is fully launched.
I favor (3) as having the best UX. But it is also the most difficult to implement.Sponsor 30 - Objective 3.3richardrichardhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/27196TB 8a10 and panopticlick: your browser has a unique fingerprint2022-01-11T19:31:57ZtraumschuleTB 8a10 and panopticlick: your browser has a unique fingerprintThe bundle works fine, thanks for your great work!
I am surprised by the new yellow blinking triangle over the onion settings button. What does it mean? (The tooltip only says "Tor Enabled")
= Update NoScript to 10.1.8.16
In NoScript p...The bundle works fine, thanks for your great work!
I am surprised by the new yellow blinking triangle over the onion settings button. What does it mean? (The tooltip only says "Tor Enabled")
= Update NoScript to 10.1.8.16
In NoScript preferences the list of per-site definitions was empty, I added a site and clicked on reset: a lot of whitelisted domains appeared (legacy/trac#26517).
= Trackers
As discussed before (legacy/trac#12958), [blocking content allows fingerprinting](https://trac.torproject.org/projects/tor/wiki/org/teams/CommunityTeam/Support_discuss#CanIinstallanewadd-onorextensioninTorBrowserlikeAdBlockPlusoruBlockOrigin), instead [[comment:4:ticket:12958|you suggest]] "an identical blocklist for every user. For example, AdBlock Plus with a fixed set of filters." Do you have plans to do this? (I am aware of your answers for [[comment:1:ticket:15279|uMatrix]] and [[comment:54:ticket:17569|ublock origin]] and spare you to repost everything :)
(mentioning [Riseup's recommendations](https://riseup.net/en/security/network-security/better-web-browsing) + requestblock for a balanced perspective, because I do not follow the conclusion that external requests should be accepted just not to be finger-printable. For me personally it's worse, when trackers know that I visited a site.)
legacy/trac#14924 sounds reasonable.
= EFF/Panopticlick
wants me to install privacybadger (not voting for it here, because of legacy/trac#12958)
Is your browser blocking tracking ads? ⚠ partial protection
Is your browser blocking invisible trackers? ⚠ partial protection
Does your blocker stop trackers that are included in the so-called “acceptable ads” whitelist? ✗ no
Does your browser unblock 3rd parties that promise to honor Do Not Track? ✗ no
Does your browser protect from fingerprinting? ✗
your browser has a unique fingerprint
https://share.riseup.net/#3RwdPLNSuFFZcK9MA_6l8g
I consider the defaults dangerous ([[comment:3:ticket:25451|window size]]). Why not setting the security slider to "Safest" per default?Erinn ClarkErinn Clarkhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/27127Audit and enable HTTP/2 push2022-10-25T21:26:34ZArthur EdelsteinAudit and enable HTTP/2 pushIn #14952 we plan to enable HTTP/2, but we are postponing enabling HTTP/2 push in case there are potential privacy concerns. Let's investigate any concerns here and hopefully enable push in the future.In #14952 we plan to enable HTTP/2, but we are postponing enabling HTTP/2 push in case there are potential privacy concerns. Let's investigate any concerns here and hopefully enable push in the future.https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/25735Tor Browser stalls while loading Facebook login page (Waiting for static.xx.f...2020-06-27T14:36:07ZTracTor Browser stalls while loading Facebook login page (Waiting for static.xx.fbcdn.net)Problem:
After opening the Tor Browser and typing in facebook.com, page loading hangs, status bar showing "Waiting for static.xx.fbcdn.net"
HTTP GET requests for small images from static.xx.fbcdn.net stall in the "Blocked" state for mi...Problem:
After opening the Tor Browser and typing in facebook.com, page loading hangs, status bar showing "Waiting for static.xx.fbcdn.net"
HTTP GET requests for small images from static.xx.fbcdn.net stall in the "Blocked" state for minutes - viewed in Developer tools / Network / request / Timing (see attached screenshot Step2.png).
When a different website is opened in a new tab, HTTP requests continue loading successfully - seems to be some livelock within the browser.
This is **not a network issue**, connectivity in the browser works fine, also verifed without a SOCKS proxy (direct connection without Tor).
Reproducibility: nearly 100%
Environment:
- Windows 10 Pro, 64bit
- Tor Browser 7.5.3 for Windows, english
- Tor Browser 8.0a5 for Windows, english
**Trac**:
**Username**: uzihttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/24698Torbrowser keeps hanging and freezing, plus it takes a very long time to load...2022-02-03T19:06:05ZTracTorbrowser keeps hanging and freezing, plus it takes a very long time to load after hibernationUsing Windows 7, 64-bit
I've had these same problems on two different laptops, both running Windows 7, 64-bit.
The past several versions of Torbrowser, including the recent 7.0.11 and 7.5a.9, the browser keeps hanging up and freezing....Using Windows 7, 64-bit
I've had these same problems on two different laptops, both running Windows 7, 64-bit.
The past several versions of Torbrowser, including the recent 7.0.11 and 7.5a.9, the browser keeps hanging up and freezing.
When the tabs are frozen, sometimes I can ctrl+tab to the next one, but the screen will be white and the address in the bar doesn't change, so it's not really changing tabs even though the highlighted tab changes.
Also, sometimes the window will additionally be on top of everything else when it's not supposed to be and I can't view any other windows. It won't restore to NOT being in front of every other program, and with it being frozen or hanging I will have to close it and start all over.
Additionally, when it does work it takes a very long time to load from hibernation to get to a point where the tabs function properly, sometimes as much as 20 minutes (with approx 15 open tabs, and that's really not many).
I will often have several tabs open and need to hibernate the computer to finish later. These problems typically occur after returning from hibernating. This keeps costing me hours of lost work.
I have tried reporting these issues several times before but have apparently not been in the right place so I hope this is the correct location to report these bugs so it can be fixed.
Thanks very much.
**Trac**:
**Username**: justmeeehttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/23770Unusually high CPU and memory usage for process plugin-countainer2020-06-27T14:36:51ZcypherpunksUnusually high CPU and memory usage for process plugin-countainerThis only seems to have appeared in these last days, plugin-countainer uses up to 270 Mb and at times has CPU usage that spikes to 30-40%.
Linux 64bits. Tor Browser 7.5a5, all addons are up-to-date (NS 5.1.1., HE 2017.10.4).This only seems to have appeared in these last days, plugin-countainer uses up to 270 Mb and at times has CPU usage that spikes to 30-40%.
Linux 64bits. Tor Browser 7.5a5, all addons are up-to-date (NS 5.1.1., HE 2017.10.4).https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/23719Make sure WebExtensions are spared from JIT disabling in higher security sett...2021-07-09T17:23:47ZcypherpunksMake sure WebExtensions are spared from JIT disabling in higher security settings (Medium-High)This could for example negatively affect HTTPS Everywhere's performance. I have however no data on whether JIT is disabled for WebExtensions in this case.This could for example negatively affect HTTPS Everywhere's performance. I have however no data on whether JIT is disabled for WebExtensions in this case.https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/22960Tor Browser crashes when IPC connection got lost2020-06-27T14:37:15ZcypherpunksTor Browser crashes when IPC connection got lostSometimes something happens during load of a new page in a tab, and then other tabs show loading circles instead of pages, and nothing happens, except increase of
```
1,696 (100.0%) -- queued-ipc-messages
└──1,696 (100.0%) ── content-par...Sometimes something happens during load of a new page in a tab, and then other tabs show loading circles instead of pages, and nothing happens, except increase of
```
1,696 (100.0%) -- queued-ipc-messages
└──1,696 (100.0%) ── content-parent(???, pid=3796, open channel, 0x133abab8, refcnt=46)
```
which leads to OOM of the main process. (Killing child process brings TBB back to mind.)https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/22089Add Decentraleyes to slighten off a bit Exit traffic and work around some CDN...2022-07-01T16:06:43ZTracAdd Decentraleyes to slighten off a bit Exit traffic and work around some CDNs blocking of TorFor those who don't know what it does: "Protects you against tracking through "free", centralized, content delivery. It prevents a lot of requests from reaching networks like Google Hosted Libraries, and serves local files to keep sites ...For those who don't know what it does: "Protects you against tracking through "free", centralized, content delivery. It prevents a lot of requests from reaching networks like Google Hosted Libraries, and serves local files to keep sites from breaking. Complements regular content blockers."[1]
For example, according to W3Techs statistics, Google Hosted Libraries is used by 16.9% of all websites, that is a JavaScript content delivery network market share of 70.4%.[2] Decentraleyes works by blocking requests to that CDN and loading the Javascript libraries locally.
That way not only some sites will load *slightly* faster (or faster for low-bandwidth clients) due to the resources being blocked and loaded locally (which also means slightly less traffic needed for exits), but also will protect from tracking by those CDNs.[3]
This addon doesn't clash with section 2.3. of the Tor Browser Design Doc with regards to ad-blockers as it isn't one.
--
[1] : https://addons.mozilla.org/en-US/firefox/addon/decentraleyes/
[2] : https://w3techs.com/technologies/overview/content_delivery/all
[3] : "The paper also makes me think about exit traffic patterns, and how to better protect people who use Tor for only a short period of time: many websites pull in resources from all over, especially resources from centralized ad sites. This risk (that it greatly speeds the rate at which an adversary watching a few exit points — or heck, a few ad sites — will be able to observe a given user's exit traffic)..." (replade ad sites with "free" CDNs ;)
https://blog.torproject.org/blog/improving-tors-anonymity-changing-guard-parameters
[4] : https://www.torproject.org/projects/torbrowser/design/ "As a general matter, we are also generally opposed to shipping an always-on Ad blocker with Tor Browser."
**Trac**:
**Username**: imageverifhttps://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/21911Tor Browser / Firefox degrades into resourse hog2022-06-21T21:56:44ZcypherpunksTor Browser / Firefox degrades into resourse hogBugzilla is full of similar bugs
```
CC(T+206349.0) max pause: 1891ms, total time: 2105ms, slices: 39, suspected: 457, visited: 32356 RCed and 273549 GCed, collected: 8121 RCed and 57395 GCed (57395|0|304 waiting for GC)
ForgetSkippable ...Bugzilla is full of similar bugs
```
CC(T+206349.0) max pause: 1891ms, total time: 2105ms, slices: 39, suspected: 457, visited: 32356 RCed and 273549 GCed, collected: 8121 RCed and 57395 GCed (57395|0|304 waiting for GC)
ForgetSkippable 19 times before CC, min: 0 ms, max: 47 ms, avg: 8 ms, total: 157 ms, max sync: 0 ms, removed: 6522
```
Some guys suspect NoScript, others - HTTPSE, but it's worth testing from the Tor Browser's side too.
(It happens with an ordinary browsing of Trac and Bugzilla.)https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/19355Firefox bug - Moving a mouse pointer over the TBB windows is CPU intensive on...2020-06-27T14:39:04ZbugzillaFirefox bug - Moving a mouse pointer over the TBB windows is CPU intensive on Windows XPMoving a mouse pointer over the TBB windows is CPU intensive (100%) on Windows XP. So be happy that FF can't use all cores.Moving a mouse pointer over the TBB windows is CPU intensive (100%) on Windows XP. So be happy that FF can't use all cores.https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/19276Scrolling is slow and CPU intensive2022-06-18T01:51:01ZcypherpunksScrolling is slow and CPU intensiveScrolling in TB 6.0 is slow and increases CPU usage to near 100%. This occurs on all pages, even simple internal ones such as `about:support`.
The issue does not occur with Firefox ESR 45.1.1.Scrolling in TB 6.0 is slow and increases CPU usage to near 100%. This occurs on all pages, even simple internal ones such as `about:support`.
The issue does not occur with Firefox ESR 45.1.1.