STR: 1. Open this URL - about:support 2. Go to "Features" to see "Compositing" value "Speedy" Regression window (mozilla-central) Good: https://ftp.mozilla.org/pub/firefox/nightly/2017/02/2017-02-13-03-02-06-mozilla-central/ Bad: https://ftp.mozilla.org/pub/firefox/nightly/2017/02/2017-02-14-03-02-31-mozilla-central/ Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=00d16f03506b7f9f754b01a0a458c05445ac6dba&tochange=195049fabb7ac5709e5f75614ba630ba3d1b5a9b Probably caused by: 61e17a4c8397 David Anderson — Give browser-process PuppetWidgets a BasicLayerManager. (bug 1287004, r=mattwoodrow) [Tracking Requested - why for this release]: Regression

From about:support Graphics Section: Compositing BasicLayers (main thread, no OMTC) Before patch is was Direct3D 11.

I'm assuming this is a reporting error, but I can't reproduce it. I'm not sure how we'd even hit this case, since PuppetWidgets are never created in the parent process. Is it possible to narrow this down further?

FYI... Some folks over at Mozillazine report that they don't have this problem. Might be OS, video card or something else related. I have this problem. I attached my Graphics info from about:support.

I discovered through trial and error that two of my add-ons, which happen to be WebExtensions, are causing the problem. Setting either one to enable causes the problem, they are not tied together. The add-ons are: Zoom Page We 3.3 History AutoDelete 1.0.0.

I can confirm this, the WebExtension TamperMonkey is causing this for me. Both on an Intel HD 520 and an AMD Radeon R9 390.

FYI... I have one other Webextension add-on that doesn't cause this problem; Password Toggler 1.1.

I can also confirm this on my laptop with a Intel(R) HD Graphics 5500 with my extension (History AutoDelete).

Great, thanks for STR! this is certainly a reporting error caused by bug 1287004.

David... Are you saying that even though it no longer says Direct3d 11 it is in fact Direct3D 11?

(In reply to Gary [:streetwolf] from comment #9) > David... Are you saying that even though it no longer says Direct3d 11 it is > in fact Direct3D 11? Right, you still have D3D11 :) something is just causing about:support to print the wrong thing.

Tracking 54+ for this user facing regression.

The bug is that WebExtensions create a windowless tab (using PuppetWidget), which confuses this layer manager iterator. I'm pretty sure we don't have non-OMTC top-level visible windows anymore, so this treats such windows as if they don't exist. Just in case we do have those windows, it reports BasicLayers if no OMTC windows were found.

Pushed by danderson@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/2f9a1529fe76 Ignore PuppetWidgets for about:support layer manager reporting. (bug 1339607, r=milan)

I'm marking this bug as VERIFIED, as it's fixed started since Mozilla Firefox Nightly 54.0a1 (2017-02-17).