These Weeks in Firefox: Issue 25

Highlights

• A browser.tabs.tabMinWidth preference has been added to control the minimum tab width before overflow, and the default was then set for 50. More recently, this default has changed to 76. Discussion is ongoing here.
• Screenshots shipped with Firefox 56!
  • Screenshots has processed over 7.5 million shots in the past 30 days
• The privacy WebExtension API can now be used to control the privacy.resistFingerprinting preference.
• Volunteer Matthieu “utybo” S. contributed a new Photon-inspired autoscroll icon which we added to the tree, replacing the old platform-specific PNGs.
• Retained display lists are going to land in Nightly 58 behind the layout.display.list.retain pref. When enabled, this should give us a boost to paint performance since we’ll be re-calculating only the display list entries that changed instead of the whole list! Relevant mailing list post.
• :Mystor added a pref to allow switch-to-tab matches to move the tab to the currently focused window, instead of switching to the tab’s window.

Friends of the Firefox team

• Resolved bugs (excluding employees): https://mzl.la/2y70Zrs
  • More than one bug fixed:
    • :prathiksha
    • Ian Moody [:Kwan]
    • Tim Nguyen :ntim
    • Tom Schuster [:evilpie]
    • Wouter Verhelst:wouter
    • [:Towkir] Ahmed
  • New contributors (🌟 = First Patch!)
    • 🌟 David Krauser added some great tests for the “categorical” type of Telemetry histograms
    • sajattack cleaned up some unnecessary strings and code for the standalone mode for about:addons (which we don’t support anymore)
    • Maya Messinger fixed a bug where the Flexible Space palette item would disappear when adding it to a toolbar via the context menu! This fix has been uplifted to beta.
    • 🌟 apoorvasingh2811 made it easier for our WebExtension infrastructure to understand extensions from the Opera browser

Project Updates

Add-ons

• browsingData is now able to remove localStorage by domain.
• browser.theme.reset() now accepts a windowId parameter.
• We now ignore the manifest key minimum_opera_version when processing a WebExtension manifest.
• Extensions can now configure Firefox security devices (PKCS#11 modules).
• Lots of performance fixes, bug fixes and code cleanup!

Activity Stream

• Update on Activity Stream on about:home for 57
  • Landed patch to restore existing about:home in Nightly, preffed off by default
  • Starting a Shield pref flip study in Nightly to compare Activity Stream to existing about:home
  • Requested uplift for patch to 57 Beta so that same study can be run there
• Started planning / landing for 58
  • Q4 OKRs
  • Doorhanger info panel and collapsible sections

Browser Architecture

• XBL design review happened last week, next step is to share the plans more widely.
• Experimenting with removing the XUL box model

Firefox Core Engineering

• New projects († are subject to approval):
  • Adding a dummy crash reporter (en route to CFI-based stackwalking)
  • Jumping in to help with Chrome migration
  • Going to be creating a policy engine & API to support policy management in enterprises (not just Active Directory)†
  • Possibly revamping how we update the DLL blocklist† in parallel with some early injection mitigation changes

Form Autofill

• Working with the SHIELD team to do the gradual rollout of address autofill in 56
  • One bug fix needs deployment first
• Continuing work on credit card autofill for the US (not riding the trains yet)
• “Clear” autofill item in progress

Photon

Performance

• Been doing a deep-dive investigation on this bug where a user reports slower page load times due to the 60fps tab throbber
  • We’ve now got hardware where we can reproduce the problem on. The clock speed is really low on these machines (even worse when in battery-saving mode), which seems to be the main contributing factor.
• Fixed a bug where logins / passwords weren’t being filled in via the context menu item – this was a regression from some perf work where the contextmenu sync IPC message was removed.
• Patches will land shortly that will allow us to kill hanging JS more quickly in content processes when we’re shutting down or when all windows have disappeared. This should eliminate a class of slow shutdowns.

Structure

• You can now drag windows from their empty space
• Polished various aspects of customize mode:
  • Made the overflow menu easier to understand
  • Dark and light themes are now always available in the theme picker
  • Make removing items via drag&drop easier
  • Make dragging non-removable items work better
  • Adding flexible spaces to the toolbar using the context menu no longer removes them from the customize mode palette
• Fixed major issues with the panel animations
  • Ongoing work in this area
• Fixed an edgecase with dragging tabs.
• Polish on the hamburger panel
  • Zoom indicator sizing
  • Width in the face of scrollbars
• Polish in the downloads views
  • Jumpiness on hover
  • Handling items that are (re)moved after download
  • Icons should be bigger

Animation

• Working on animating the sidebar appearing/disappearing

Visuals

• Special thanks to our volunteer :Towkir who updated even more icons to the Photon style (bookmarks toolbar dropzone, about:license) and fixed some color issues with icons he previously added!
• Dão removed -moz-appearance: -moz-win-glass; from Windows 10 windows, which fixed a bunch of issues and caused a few new bugs to surface.
• Johann made tab separators not disappear when hovering tabs.
• Johann added additional drag space to the right of windows.
• Dale updated the search bar icon to use the new Photon icon.
• A few polish fixes for popup windows.
• And a lot of other bugfixes.

Platform Audibles

• The DOM team is going to be even more aggressive about throttling back timers in background tabs.

Search and Navigation

• Fixed various regressions in the Address Bar:
  • text cropped at the wrong point
  • removing history entries using DEL/Shift+DEL
  • matches now are properly aligned in the popup. As a bonus the change removed a large number of potential reflows and some jank. 🎉🎉🎉
• Some more Async Places Transactions fixes, feature still planned for 58.
• investigated a large number of frequent intermittent failures
• Experiments:
  • Resolved a perf issue in the Follow-on Search System Add-on, slowing down opening tabs
  • A new Search Hijacking prevention experiment was launched last week. Results will be available for analysis in a couple of weeks.
  • Based on the results from the most recent unified urlbar experiments, we’ll soon land a new mixture of results for the Address Bar
• Contributions from outside of the team:
  • :Kaie: fixed a longstanding (6 years old) bug in how we initialize Sqlite, so that NSS and mozStorage can coexist in a saner way in Firefox.
  • :Gijs fixed a security bug about pasting specially crafted javascript urls into the Address Bar
  • :Mats fixed copying urls containing multiple spaces from the Address Bar

Test Pilot

• We wrote a Pulse graduation report
• Results of first a/b test on send.firefox.com

Here are the raw meeting notes that were used to derive this list.

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