STR:

1. Set browser.ssb.enabled = true.
2. Install uBlock Origin extension.
3. Start with firefox -ssb bugzilla.mozilla.org

Expected:

Page appears.

Actual:

Blank window.

P3 for fx general in the sense that we don't have spare people who could go fix this, though I imagine this impacts quite a few people testing on nightly so it might be higher priority for the SSB testing - I think the webextensions core code might be holding up requests until startup happens in order for add-ons to have a chance to block them, but if the webextension code never thinks startup happens then nothing loads. Dave, feel free to take this and/or bug 1603089 and increase priority.

Given that this is all still preffed off I think the priority is fine, though that said I intend to try to work on bug 1603089 next week.

I have not been able to reproduce this in both ways. Bugzilla loads with uBlock on and the apps that don't load (Spotify, Deezer, Mastodon.social) also won't load with it disabled. Are these separate bugs or could your uBlock-cause thesis be incorrect?

(In reply to netsurfer912 from comment #3)

Bugzilla, Spotify, Deezer, Mastodon.social

For me they all work with uBlock disabled and fail (white screen) with uBlock enabled. Make sure you are testing in a new profile with the minimum number of changes required.

I would like to report that this happens not only with ublock, but also with ghostery and adblock plus.

My workaround (based in part on comments above)

1. i created a new profile
2. Installed, but forbid ublock from running in private windows
3. Manually created the desktop icon with -ssb, URL and -private arguments

As a result I have ublock running on normal windows but ssb, as they are private, are not affected.

Comment on attachment 9188865 [details]
ssb_gui_button

Issue occur to me only when launching firefox with -ssb switch.

Use This Site in App Mode button works fine.

(In reply to t3udveljdh7 from comment #7)

Comment on attachment 9188865 [details]
ssb_gui_button

Issue occur to me only when launching firefox with -ssb switch.

Use This Site in App Mode button works fine.

If any instance of firefox is already running you won't have any problem. The issue occurs only when you start firefox directly in -ssb mode (e.g.: from a desktop shortcut).

it's really a shame, because we have to use chrome if we need something like this.

Closing per bug 1682593.