Specification

https://w3c.github.io/window-management/

Explainer

https://github.com/w3c/window-management/blob/main/EXPLAINER_additional_windowing_controls.md

Links

• The WG's request for this TAG review: https://lists.w3.org/Archives/Public/public-secondscreen/2026Jul/0004.html
• An introduction to the feature, aimed at unfamiliar audiences: https://github.com/w3c/window-management/blob/main/EXPLAINER_additional_windowing_controls.md#introduction
• A description of the problems that end-users were facing before this proposal: https://github.com/w3c/window-management/blob/main/EXPLAINER_additional_windowing_controls.md#problem-and-use-cases
• Alternatives considered: https://github.com/w3c/window-management/blob/main/EXPLAINER_additional_windowing_controls.md#alternatives-considered
• Examples of how to use the proposal to solve the end-users' problems: https://github.com/w3c/window-management/blob/main/EXPLAINER_additional_windowing_controls.md#proposal
• What do the end-users experience with this proposal:
  • https://github.com/patrykchodur/awc-demo
  • https://awc-demo-4a08a808.web.app/ (required chrome://flags#enable-desktop-pwas-additional-windowing-controls)
• Web Platform Tests:
  • https://wpt.fyi/results/css/mediaqueries/display-state.tentative.html
  • https://wpt.fyi/results/css/mediaqueries/resizable.tentative.html
  • https://wpt.fyi/results/window-management/additional-windowing-controls.tentative.https.html
• Security/Privacy Questionnaire: https://github.com/w3c/window-management/blob/main/security_and_privacy_additional_windowing_controls.md

The specification

• Follows the Web Platform Design Principles.
• Includes Security and Privacy Considerations sections based on answers to the Security/Privacy Questionnaire.

Where and by whom is the work is being done?

• GitHub repo: https://github.com/w3c/window-management
• Primary contacts:
  • Patryk Chodur (@patrykchodur), Google, Editor
  • Mike Wasserman (@michaelwasserman), Google, Editor
• Organization/project driving the specification: Google Chrome team
• This work is being funded by: Google
• Primary standards group developing this feature: Second Screen Working Group
• Incubation and standards groups that have discussed the design:
  • CSS WG - window.onmove event proposal that was removed from the specification - https://github.com/w3c/csswg-drafts/issues/7693#issuecomment-2842594228
  • Second Screen WG - https://github.com/w3c/window-management/issues/158

Feedback so far

• Active horizontal reviews:
• Multi-stakeholder feedback:
  • Chromium comments:
  • Mozilla comments:
    • Additional Windowing Controls - https://github.com/mozilla/standards-positions/issues/712
    • Window Management (host spec) - https://github.com/mozilla/standards-positions/issues/542
  • WebKit comments:
    • Additional Windowing Controls - https://github.com/WebKit/standards-positions/issues/96
    • Window Management (host spec) - https://github.com/WebKit/standards-positions/issues/117
• Major unresolved issues with or opposition to this specification:
• Status/issue trackers for implementations:
  • https://chromestatus.com/feature/5201832664629248
• CSS Working Group issue for proposed media features:
  • https://github.com/w3c/csswg-drafts/issues/14428

You should also know that...

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