Firefox Profiler Dark Mode and Updated Smart Window Prompts - These Weeks in Firefox: Issue 197

[Katherine Patenio]

Hi firefox-dev,

Continuing from Mike Conley's previous "These Weeks in Firefox" email earlier this month, I'd like to share the next issue (the 197th, in fact) of Firefox Desktop engineering updates. Here, you can find a summarized version of our meeting notes from several weeks ago.

We're still catching up on our backlog, so keep an eye out for more updates in the coming days. Happy reading!

Highlights

• Smart Window added contextual prompts for follow-ups bug 2012208 and conversation starters bug 2014946

• [screenshot]

• alt text: Smart Window showing prompts "How does Firefox protect my privacy?" and "What does Mozilla do with AI?".

• [screenshot]

• alt text: Smart Window showing prompts "Explain Mozilla's mission in simple terms" and "Compare Mozilla to other browsers."

• SplitView is approaching completion in Nightly and hopes to ride the trains soon. If you see something, say something (File a bug in Firefox: Tabbed Browser: Split View)

• [screenshot]

• alt text: Firefox SplitView showing two pages side-by-side, one about Wensleydale cheese and the other about Cheshire cheese.

• Session History (Jake Diagrams) is now available in DevTools

• Andreas Farre [:farre] added a sidebar in the Application panel to show Session History data (aka Jake Diagrams) (#2013007)

• [screenshot]

• alt text: Session History within the Application panel in DevTools.

• Set behind a pref devtools.application.sessionHistory.enabled. Feel free to try it out!

• The Firefox Profiler now supports dark mode thanks to :arai!

• [screenshot]

• alt text: Firefox Profiler with dark mode theming enabled.

• [screenshot]

• alt text: Firefox Profiler dark mode settings.

Friends of the Firefox team

Resolved bugs (excluding employees)

Volunteers that fixed more than one bug

• Beatriz Rizental

• Chris Vander Linden

• Khalid AlHaddad

New contributors (🌟 = first patch)

• 🌟Alex Leykin [:alexff]: Firefox’s new ‘pinned web apps / taskbar web apps’ windows (Firefox 143 on Windows 11) don’t remember their size or position after being moved/resized and reopened

• 🌟Jacob: downloaded files do not respect referrer-policy when setting kMDItemWhereFroms

•  Leonardo Paffi: Add capability for loadTestPage to take inline HTML

•  Phil [:phigl]: Request size is wrong when request is served from cache

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Fixed issue hit by concurrent installations due to error handling potentially removing the entire staging directory used by the other concurrent XPI files pending installation - Bug 2006512

• Fixed issue with "Available Updated" badge counter getting out of sync - Bug 1548836

WebExtensions Framework

• Disabled dom.keyboardevent.init_key_event.enabled_in_addons preference on all channels - Bug 2015079 / Bug 2013772

• NOTE: The deprecated feature has been disabled for the release channel in Firefox versions >= 147. Users still using the discontinued 1password classic extension should migrate to the maintained 1password extension or migrate to another maintained password manager.

• Investigated and fixed excessive process creation on rapidly clicking extension icons (e.g., uBlock) - Bug 1987679 / Bug 2007742

WebExtension APIs

• Exposed splitViewId property in tabs extension API to support split view feature - Bug 1993037

• Improved cross-browser compatibility for the browserAction and pageAction openPopup API method, in particular allowing it to be called without user interaction (which is an ability that password managers leverages) - Bug 1799344 / Bug 1799347 / Bug 2011516

• Fixed issue with browser.storage.onChanged API event not emitted for object writes after opening Storage tab in DevTools - Bug 1994355

• Deprecating executeScript API methods support for dynamically executing code into moz-extension documents - Bug 2011234

• NOTE: This deprecation is in the process of being documented and communicated to extensions developers. The restriction is active by default on Nightly, whereas it will be logging a deprecation warning on Beta and Release channels.

DevTools

• Chris Vander Linden refactored AccessibilityRow.js and accessibility/panel.js to use proper ES private fields (#2015237, #2015238)

• Phil [:phigl] fixed the request size of cached request in Netmonitor (#1973003)

• Nicolas Chevobbe [:nchevobbe] added tooltip to show value of attribute in attr() function (#2011646)
• [screenshot]
• alt text: Tooltip displaying the value of an attribute as "earth" in Devtools.

• Julian Descottes [:jdescottes] made it possible to use Network Throttling in the Browser Toolbox (#2015030)

• Nicolas Chevobbe [:nchevobbe] fixed an issue where the content dialog (e.g. alert()) were covering the DevTools toolbox (#2013120)

• Nicolas Chevobbe [:nchevobbe] added inactive CSS indicator for position-area when the element is not absolutely positioned, and/or doesn't have a default anchor  (#1895185)

• Julian Descottes [:jdescottes] similarly fixed an issue with the Browser Screenshot popup being displayed oddly when RDM is enabled (#2016109)

Information Management/Sidebar

• We’ve started making xul:splitter keyboard accessible. Bug 2012633 - Splitter component is not accessible landed for splitview splitter. There are others across the product that can make it focusable.

New Tab Page

• With the startup crash fixed, train-hopping has been unblocked! 149.1.20260121.51415 went out to the release and beta channels recently.

• Nathan Barrett fixed reordered Top Sites showing mismatched names/icons after restart when placed after Add Shortcut, correcting persisted tile indexing in Activity Stream so Top Sites render with the right metadata across sessions.

• Maxx Crawford added thumbnail attachment to uploaded wallpapers, using the generated thumbnail for previews in the Customize panel to speed image rendering and reduce decode cost while keeping full‑res when applied.

• Nathan Barrett enabled the image proxy backend for newtab, giving us the ability to route newtab image requests through a third-party proxy for better privacy characteristics. This is disabled by default while we investigate proxying strategies.

• Mike Conley added activation window experiment messaging variants on newtab. This is something we expect to experiment with for new installs starting later this month.

• Maxx Crawford replaced the Weather widget context menu with the shared panel‑list, unifying menu styling and improving keyboard/focus behavior on the New Tab Page.

• Irene Ni removed auto-placement logic for the Weather widget, preventing unexpected moves and reducing layout shifts so the widget consistently stays where users place it.

Performance Tools (aka Firefox Profiler)

• You can now copy the marker table as a markdown or plain text.

• [screenshot]

• alt text: Firefox Profiler with new dropwdown options to copy data from the marker table.

• Added a “Focus on self only” transform.

• Stack Chart now includes traced values if you have “JS execution tracing” feature enabled.

Search and Navigation

• Moritz corrected various misbehaviors of the new Search Bar widget:

• The search bar should properly overflow, and work in the overflow panel - Bug 2006023
• Go button was missing when dropping text into the search bar - Bug 2013536
• Go button used the previous search engine after changing the default engine - Bug 2013883
• The suggestions panel was appearing behind the urlbar when in menubar Bug 2007147
• Couldn’t remove search bar history entries - Bug 2014258

• Suggest:

• Drew enabled online Suggest (ohttp) for eligible users in Nightly: Bug 1998009, Bug 1996952, Bug 2014318, Bug 2014296
• Drew fixed Show Less Frequently option for Add-on suggestions Bug 2011853

• Other notable fixes:

• Dharma improved name matching for the contextual search feature Bug 2003798
• Dale fixed a bug where the number of blocked trackers was wrongly reset in the trust panel when reloading the page Bug 2011494

Smart Window

• More Smart Window updates:

• Smartbar with autofill with appropriate cta (go vs search vs ask) bug 2008926 and suggestions list bug 2008977

• [screenshot]

• alt text: Smart bar feature with www.mozilla.org in the search bar and a "Go" button to run the search.

• Conversations stay with a tab when shifting from fullpage to sidebar assistant bug 2012536

• Session restore smart window status for all windows bug 2010901

• Hooking up footer actions, e.g., copy, retry without memories bug 2010189

• Preferences show get started bug 2014852 vs personalization with browser.smartwindow.enabled bug 2014537

• Handling error cases including 401 token expiration bug 2015116 and showing them in conversation bug 2010417

Below the fold

General Triage

• Mark Banner, Eemeli Aro, Marco Bonardo, and Mortiz Beier are this month’s Firefox / Toolkit :: General triagers!

This week I learned

• [nicolas] - searchfox updates! TWIL searchfox has multiple modes - alpha, beta, stable. if you switch to alpha, there's a section to configure searchfox to tell it where your local repo is, then there's an "open in editor" integration!

--

This information, including all of the previous updates, are fully available in this doc: https://docs.google.com/a/mozilla.com/document/d/1u9YH3ULNRYg6G-fN-Udkvfkcvg0alJfzi_zIAfFNkL8/edit?usp=sharing

Also note that we’re really just synthesising and humanising the stuff that's on the Wiki, which is freely available from here: https://wiki.mozilla.org/Firefox/Meeting, so check that out if you want the source material. It'll also be posted (minus the Below the Fold stuff) to the Nightly blog.

Finally, if there's a Firefox-ish team that you feel isn't being represented here, please let them know about the above meeting so we can get their updates.

Keep on rockin' the free web,

kpatenio