59.0a1 (2017-12-04) (64-Bit) macOS 10.12.6 1.) Open a new window 2.) Open some NewTabs 3.) Take a look at the title Actual: Sometimes the NewTab title flickers Expected: No flicker. A screencast is attached. Take a look at the second tab in the screencast.

Here is another screencast showing the flicker, when you start Nightly. If you need more information, please let me know. Thanks.

Bug 1423256 might be related as it's relying outside of activity stream page content to set the appropriate title?

I attached a video showing Firefox starting up after a restart (which is supposed to be the slowest scenario, on a slow machine which is known to be slow). I am no longer seeing the issue. Could you test again in latest nightly and confirm? Thank you.

(In reply to Andrei Oprea [:andreio] from comment #3) > Created attachment 8943195 [details] > flicker_test_refhardware.mp4 > > I attached a video showing Firefox starting up after a restart (which is > supposed to be the slowest scenario, on a slow machine which is known to be > slow). I am no longer seeing the issue. > Could you test again in latest nightly and confirm? Thank you. Yep, it is fixed for me too in 59.0a1 (2018-01-17) (64-Bit) on macOS 10.12.6.