1577509 - With Fission enabled, switching to a discarded tab always results in a short tab switch spinner

Status: RESOLVED WORKSFORME

(Firefox :: Tabbed Browser, defect, P3)

Description

[Mike Conley (:mconley) (:⚙️)]

STR:

1. Enable Fission (set fission.autostart to true and restart)
2. Browse to mozilla.org in the initial tab
3. Click on the shield icon in the URL bar, and choose "Protection Settings"
4. In the newly opened about:preferences tab, change the default protection settings, and click on the "Reload All Tabs" button
5. Switch back to the original tab

ER:

No tab switch spinner - if anything, we should show blank until the tab contents are loaded and ready.

AR:

A short tab switch spinner is shown.

I noticed this while investigating bug 1575610, but doesn't appear to be a recent regression (we've been doing this since before August 7th, 2019), so I don't think it's responsible for the spike that bug 1575610 is concerned with.

Comment 1

[Chris Peterson [:cpeterson]]

Tentatively moving all bugs whose summaries mention "Fission" (or other Fission-related keywords) but are not assigned to a Fission Milestone to the "?" triage milestone.

This will generate a lot of bugmail, so you can filter your bugmail for the following UUID and delete them en masse:

0ee3c76a-bc79-4eb2-8d12-05dc0b68e732

Comment 2

[Chris Peterson [:cpeterson]]

Tentatively resolving this bug as WFM because I can't reproduce it (ten months since it was filed) in 79 Nightly. If you can still repro, please reopen this bug.