The section won't display when having at least browser.preferences.search=false or identity.fxaccounts.enabled=false

why is this important?

Because it was not visible I thought the 'Firefox Home Content' section was to be a future enhancement when about:preferences#home was enabled; only after trying a new profile I saw this was not the case and found this setting was the culprit after adding my customizations one by one. Setting identity.fxaccounts.enabled=false has been mentioned elsewhere in order to disable the Sync features (Cloud paranoid here); it has no UI in about:preferences so it may not meet the 'important' criteria.

Marking as a regression since it was possible to customize the new tab page in previous versions with Sync disabled.

Is this just because we're listening for the "sync-pane-loaded" event to inject elements?

Comment on attachment 8982082 [details] Bug 1447879 - Cannot customize about:preferences#home content when sync or preference searching is disabled. https://reviewboard.mozilla.org/r/248126/#review254456 Works for me!

Pushed by edilee@gmail.com: https://hg.mozilla.org/integration/autoland/rev/0dc7bfc7b0c1 Cannot customize about:preferences#home content when sync or preference searching is disabled. r=k88hudson

Please request Beta approval on this when you get a chance.

The issue is no longer reproducible on the latest Nightly 62.0a1 (Build ID 20180604100129) on Windows 10 x64, Mac 10.12.6 and Ubuntu 16.04 x32. The "Firefox Home Content" section is still displayed when "browser.preferences.search" or "identity.fxaccounts.enabled" (or both) are set to false.

Commit pushed to master at https://github.com/mozilla/activity-stream https://github.com/mozilla/activity-stream/commit/2eeb2031a323ff3bf0a7685dfb0aef41ddfa21cb chore(mc): Port Bug 1447879 - Cannot customize about:preferences#home content when sync or preference searching is disabled. r=k88hudson

Comment on attachment 8982082 [details] Bug 1447879 - Cannot customize about:preferences#home content when sync or preference searching is disabled. Approval Request Comment [Feature/Bug causing the regression]: Bug 1404890 first implementing Firefox Home content preferences used the existing pattern of waiting for sync prefs to load before adding more preferences. [User impact if declined]: Unable to customize Firefox Home content [Is this code covered by automated tests?]: No [Has the fix been verified in Nightly?]: Yes comment 10 [Needs manual test from QE? If yes, steps to reproduce]: No [List of other uplifts needed for the feature/fix]: None [Is the change risky?]: A little [Why is the change risky/not risky?]: There's a known talos regression bug 1466472, which currently is unresolved, but my investigation there is that we should accept the "regression" which is actually a improvement on when the preference content actually shows up to the user. [String changes made/needed]: None

Comment on attachment 8982082 [details] Bug 1447879 - Cannot customize about:preferences#home content when sync or preference searching is disabled. Fixes broken customization of Firefox Home. The Talos regression was deemed to not be an issue. Approved for 61.0b14.

I managed to reproduce the initial issue on 61.0a1 (2018-03-24). I also can confirm that 61.0b14 build1 (20180614135649) is verified fixed across platforms (Windows 10 x64, Ubuntu 16.04 x64, macOS 10.12.6).