We're looking at enabling Screenshots in mochitests by default. In browser_BrowserUITelemetry_defaults.js we're seeing this test failure: 1879 INFO TEST-UNEXPECTED-FAIL | browser/modules/test/browser/browser_BrowserUITelemetry_defaults.js | No other test should have left CUI in a dirty state. - false == true - JS frame :: chrome://mochitests/content/browser/browser/modules/test/browser/browser_BrowserUITelemetry_defaults.js :: test :: line 15 Stack trace: chrome://mochitests/content/browser/browser/modules/test/browser/browser_BrowserUITelemetry_defaults.js:test:15 chrome://mochikit/content/browser-test.js:Tester_execTest:771 chrome://mochikit/content/browser-test.js:Tester.prototype.nextTest</<:672 chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:SimpleTest.waitForFocus/waitForFocusInner/focusedOrLoaded/<:791 Buffered messages finished

I have a patch for this bug, however I think it depends on bug 1356256 as we're currently seeing inconsistent start-ups for Screenshots in tests.

(In reply to Mark Banner (:standard8) from comment #1) > I have a patch for this bug, however I think it depends on bug 1356256 as > we're currently seeing inconsistent start-ups for Screenshots in tests. Ok, I was wrong about that, I think we should land this now to avoid issues with restore defaults (Screenshots is currently disabled by default in tests, we'll get it enabled soon).

Comment on attachment 8860145 [details] Bug 1358097 - Add Screenshots to the navbar placements for Customizable UI when Screenshots is enabled. https://reviewboard.mozilla.org/r/132176/#review135272 ::: browser/components/customizableui/CustomizableUI.jsm:260 (Diff revision 1) > + // Firefox Screenshots is a WebExtension, and WebExtensions place buttons > + // at the end of the toolbar. Apparently this happens after pocket's > + // createWidget call (see previous comment). This sounds like a race condition waiting to happen, especially in the "migration" case for pocket (for profiles that had the add-on before). We should stop hacking around this and fix bug 1247045 instead. Now that we're deprecating non-webextension buttons we can just change the API to no longer prevent opting in to "real" default buttons.

I guess somewhere along the line this got fixed/worked around, since screenshots is now enabled by default.