Summary of the Pull Request

Fix unreadable caption-button glyphs and Markdown code in the separate What's New window when the PowerToys theme differs from Windows' default app mode.

With Windows Dark and PowerToys Light, minimize/maximize/close glyphs and inline-code text can be almost white on a light surface. The caption issue is a regression; the Markdown code-brush gap predates it.

This is a targeted follow-up to #48910 and #49786, not a revert of the shared native title-bar implementation.

Before / after screenshots

Both captures use Windows Dark + PowerToys Light and display the same April 2026 release notes. The displayed v0.99.1 is the notes' version, not the executable's version.

Before: installed v0.102.2911.0

The minimize/maximize/close glyphs are almost invisible against the light title bar. Inline-code examples such as DockSettings, settings.json, G, and Win also have nearly white text on a pale background.

After: patched local x64 Debug Settings

Caption glyphs and inline-code text are readable, while the existing heading/link styling is retained.

PR Checklist

• 
  Related work: #48910, #49786; no existing issue is closed by this PR.


• [ ] Communication: Separate contributor agreement has not been established; this follows the previously identified theme-override concern linked below.


• [x] Tests: Added a repeatable UI regression-capture script; existing focused Settings tests pass. Screenshot review remains manual, not an automated contrast assertion.


• [x] Localization: No new user-facing strings.


• 
  Dev docs / product documentation / new binaries: Not applicable; no new dependencies, settings fields, IPC contracts, or installer entries.

Detailed Description of the Pull Request / Additional comments

Caption buttons: follow the window, not Windows' default app mode

TitleBarTheme.UseDefaultAppMode follows Windows' default app mode. Settings applies its own Light/Dark preference to the window content, so these can disagree.

• Add an explicit-theme overload to src/common/Common.UI.Controls/Window/TitleBarHelper.cs. Preserve the original one-argument API, its Windows-default behavior, and the supported-platform guard.


• In src/settings-ui/Settings.UI/SettingsXAML/ScoobeWindow.xaml.cs, apply the initial content theme after InitializeComponent, then set native TitleBarTheme.Light/Dark from the root's resolved ActualTheme.


• Track live ActualThemeChanged events and unsubscribe when the window closes.

This retains #49786's shared helper and native caption rendering rather than restoring manually assigned caption-button colors. Other windows/modules keep their existing one-argument behavior; this PR does not broaden the change to OOBE or Shortcut Conflict.

Markdown: extend the existing element-theme workaround to code

The pinned Markdown control captures brushes from application resources rather than the selected element theme. The existing workaround corrects headings and links, but not inline/fenced-code foreground, background, or border brushes.

In ScoobeReleaseNotesPage.xaml / .xaml.cs:

• Resolve code-surface brushes through a collapsed, noninteractive, theme-aware provider, following the existing link-provider pattern.


• Apply the element-themed primary foreground and code background/border to both inline-code and fenced-code theme properties.


• Retain heading/link handling and the existing re-render path on theme changes.

No hardcoded palette or dependency upgrade is introduced. The workaround still points to the pending upstream fix, CommunityToolkit/Labs-Windows#785.

Investigation timeline

Date (UTC)
Change / inspected release
Relevance

April 29, 2026
v0.99.1
Inspected source already has the Markdown code-brush problem; the old code-rendering issue is not explained by the later caption regression.

June 29, 2026
#48910, merged 18:33:41
Corrected What's New headings/links and tracked the actual window theme for caption colors. It did not correct code brushes.

August 25, 2026
v0.101.2362.0
Contains the June caption handling, before its September replacement. This explains correct caption icons but unreadable code in the older comparison build.

September 2, 2026
#49786, merged 14:58:31
Adopted the shared native UseDefaultAppMode helper and explicitly removed the SCOOBE caption handling as redundant. This lost the app-specific theme override.

September 21, 2026
v0.101.2632.0
Already contains the September replacement: the caption regression predates the October candidate.

October 16 / 19, 2026
v0.102.2883.0 / v0.102.2911.0
Both contain the replacement; the reported mixed-theme symptoms were reproduced on installed 2911.

49786's consolidation and native theme-change fixes were intentional. Its history does not establish an intent to drop PowerToys' independent theme preference. An inline discussion posted at 15:00:33 UTC, about two minutes after merge, already identifies that UseDefaultAppMode does not follow RequestedTheme and recommends tracking ActualTheme.

Release containment above comes from source/tag inspection, not a runtime bisect of every listed installer. The April version displayed inside What's New is release-note content, not the installed executable's version.

Validation Steps Performed

• Built the release-targeted x64 Debug candidate with tools\build\build-essentials.ps1, including runner and Settings; no replacement of the installed PowerToys binaries.


• Built the Settings unit-test project and ran ScoobeReleaseTests plus ViewModelTests.General with vstest.console.exe: 18 passed, 0 failed.


• Visually checked the same What's New window with Windows Dark while selecting PowerToys Light -> Dark -> Windows default -> Light. Caption glyphs, headings, links, and April's inline-code examples (DockSettings, settings.json, G, Win) remain readable.


• The reporter also inspected the patched window and confirmed it looks correct.


• Restored the original PowerToys Light setting after the capture.


• Ported the identical four production files onto current main, avoiding unrelated stable-branch history.


• Repeated build-essentials.ps1 -Platform x64 -Configuration Debug on the actual main-based PR branch: solution restore, runner and Settings all succeeded with zero MSBuild errors/warnings.


• Rebuilt the Settings test project on that branch and repeated the same focused test run: 18 passed, 0 failed.

The checked-in src\settings-ui\Settings.UITests\Test-WhatsNewTheme.ps1 repeats that live-switch capture, checks that the same notes window survives, verifies the selected theme, restores the original app theme, and writes PNGs plus a JSON receipt. It requires an explicitly selected Settings PID and checks its executable identity. Run from the checkout after opening General and a separate What's New window containing code:

.\src\settings-ui\Settings.UITests\Test-WhatsNewTheme.ps1 -AppPid <settings-process-id>

The script uses English UI labels and winapp CLI. Its default executable is the checkout's x64 Debug build; use -ExpectedExecutable when deliberately comparing a different build. Review the PNGs manually; a successful capture is not a visual PASS.

Remaining manual coverage

• Windows Light + PowerToys Dark, and high-contrast transitions.


• Caption hover, inactive, and maximized states.


• Actual fenced-code rendering: the corresponding renderer properties compile and its implementation was inspected, but no retained fenced-code fixture was found in the fetched stable notes after installer-hash sections were removed.

These are explicitly unverified, not claimed as passing. No full release/module verification is claimed.