microsoft/microsoft-ui-reactor

Reactor is an experimental set of extensions to WinUI

Stars: 646
Forks: 54
Open beginner issues: 0
Indexed issues: 70
Avg merge: 1d 3h
Merged PRs (30d): 84

Dominant language: C#
License: MIT
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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70 open issues indexed

RN harness projects depend on react-native-windows@1.0.0, a placeholder package with no code — `npm run windows` cannot build Open

dependencies

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/microsoft-ui-reactor#1177 · Opened Sep 3, 2026
Nothing gates the CI-repro build command against `ci.yml` — three docs now duplicate it Open

ci documentation tech-debt

Difficulty 3/5 1-2 days Newbie friendliness 74/100

microsoft/microsoft-ui-reactor#1167 · Opened Sep 1, 2026
[Flaky] AOT Selftests: process dies mid-run at fixture 481/1459 with no TAP trailer and no `not ok` Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/microsoft-ui-reactor#1152 · Opened Aug 28, 2026
tools/reviewer overstates coverage: 147 of 633 manifest paths are dead Open

bug tech-debt

Difficulty 4/5 3-5 days Newbie friendliness 58/100

microsoft/microsoft-ui-reactor#1134 · Opened Aug 26, 2026
Reactor.Cli can't build offline: one command forces a build-time npm download Open

tech-debt

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#1133 · Opened Aug 26, 2026
mur loc extract treats Segoe Fluent icon glyphs as translatable strings Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 68/100

microsoft/microsoft-ui-reactor#1132 · Opened Aug 26, 2026
[Feature] Realign minver `-p experimental.0` to `preview.0` before the first stable tag Open

enhancement needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/microsoft-ui-reactor#1127 · Opened Aug 25, 2026
[CI] Docs tier-drift's path filter watches the templates but not docs/guide, so a change to the generated output alone skips the only gate that checks it Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

microsoft/microsoft-ui-reactor#1059 · 2 comments · Opened Aug 1, 2026
[Feature] Resolve gallery-lint shadowing with SemanticModel instead of a syntactic scope walk Open

enhancement needs-triage

Difficulty 5/5 Over a week Newbie friendliness 42/100

microsoft/microsoft-ui-reactor#1058 · Opened Aug 1, 2026
[Test-gate] ReadCleanElementCommonBlock matches over comments — false-green in one consumer, false-red in the other Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/microsoft-ui-reactor#1054 · 1 comment · Opened Aug 1, 2026
[Bug] One malformed XML doc comment silently disables *all* XML-doc diagnostics repo-wide (CS1574/CS1591 never computed) Open

bug needs-triage

Difficulty 1/5 Under an hour Newbie friendliness 82/100

microsoft/microsoft-ui-reactor#1053 · 2 comments · Opened Aug 1, 2026
[Bug] Attached-property exclusion list accepts instance DPs: the diagnostic recommends it, and no test reads the reason Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/microsoft-ui-reactor#1048 · 1 comment · Opened Aug 1, 2026
[Bug] AOT Selftests intermittently exits 1 with no failing test and no TAP trailer — a host crash distinct from #988, and misattributed to it Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#1046 · Opened Aug 1, 2026
[Bug] WinAppUi.SendKeys is fail-open: an unmapped key token exits 0 and types nothing, so every E2E inherits an instrument that cannot report failure Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 67/100

microsoft/microsoft-ui-reactor#1042 · Opened Aug 1, 2026
Selftest: HostCtrlFactory_Mounted/_PropsApplied flake under the coverage collector — the one fixed-delay gate 5a6bddb2 left unconverted Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

microsoft/microsoft-ui-reactor#1041 · 1 comment · Opened Aug 1, 2026
[Flaky] CompilationLoaderTests.Cold_load_under_500ms_warm_under_50ms_for_minimal_project — wall-clock budget assertion is coupled to machine load, not to the loader Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 62/100

microsoft/microsoft-ui-reactor#1040 · 1 comment · Opened Aug 1, 2026
[Bug] Pooled Grid never releases BorderThickness/BorderBrush — ElementPool.CleanElement has no border-box clear for concrete panels Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

microsoft/microsoft-ui-reactor#1039 · Opened Aug 1, 2026
tests/Reactor.Compile.Analyzer.Tests runs in no CI workflow — 11 tests that cannot fail Open

testing

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

microsoft/microsoft-ui-reactor#1038 · 3 comments · Opened Aug 1, 2026
Flaky: `ExitTr_Removed` + 3 sibling exit-transition fixtures fail intermittently in the AOT Selftests leg (reproduces on `main`) Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#1037 · Opened Aug 1, 2026
ApiIndexGeneratorTests.Index_IsUpToDate verifies one of the two committed API index copies, and its failure message recruits you into that narrower check Open

testing

Difficulty 1/5 Under an hour Newbie friendliness 88/100

microsoft/microsoft-ui-reactor#1035 · 4 comments · Opened Aug 1, 2026
`mur docs`: CLI-supplied `--topic` reaches `Path.Combine` as the later segment, so a rooted value silently relocates the base Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 86/100

microsoft/microsoft-ui-reactor#1034 · Opened Aug 1, 2026
Selftest: `Issue717_PinReleasedAfterRecovery` cannot detect "the pin never engaged", and `Issue717_Collapse_Pinned*` go vacuously green when their control fails Open

bug tests

Difficulty 3/5 1-2 days Newbie friendliness 70/100

microsoft/microsoft-ui-reactor#1033 · Opened Aug 1, 2026
[Feature] Architecture test: no static ConditionalWeakTable keyed by a poolable control type may live inside a generic type Open

enhancement needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 52/100

microsoft/microsoft-ui-reactor#1032 · 3 comments · Opened Aug 1, 2026
[Bug] SourceSnippetSanityTests anchors repo-root on CWD, not AppContext.BaseDirectory — can validate a sibling worktree Open

bug needs-triage

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

microsoft/microsoft-ui-reactor#1031 · Opened Aug 1, 2026
[Bug] Failed builds report green: documented `--no-build` loop, and `dotnet test` gates keyed on "Failed" are inverted Open

bug needs-triage

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

microsoft/microsoft-ui-reactor#1029 · 3 comments · Opened Aug 1, 2026
Gallery snippet lint doesn't catch no-op handlers in a snippet whose live card wires real ones Open

bug samples

Difficulty 4/5 3-5 days Newbie friendliness 58/100

microsoft/microsoft-ui-reactor#1028 · 2 comments · Opened Aug 1, 2026
reactor-search-index.json declares itself a generated artifact but has no merge driver — 5 open PRs, 4 blobs, silent auto-merge Open

build

Difficulty 3/5 1-2 days Newbie friendliness 55/100

microsoft/microsoft-ui-reactor#1026 · 2 comments · Opened Aug 1, 2026
[Bug] Selftest/E2E fixture registries: a fixture registered only in the `Create()`/`Build()` switch is silently never run, and CI cannot detect it Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 58/100

microsoft/microsoft-ui-reactor#1025 · 6 comments · Opened Aug 1, 2026
[Bug] Row-edit backward test: two entailed assertions, and its "differential isolation" block compares two arms that converge Open

bug needs-triage

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

microsoft/microsoft-ui-reactor#1022 · 1 comment · Opened Aug 1, 2026
[Bug] Selftest `UseIsCovered_RerendersOnZOrderChange` fails ~3 of 5 runs in isolation Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/microsoft-ui-reactor#1021 · Opened Aug 1, 2026
[Bug] Search-index generator silently falls through to the next SampleCard when a snippet *comment* trips the placeholder regex — byte-compare gate can't catch it Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 65/100

microsoft/microsoft-ui-reactor#1020 · 2 comments · Opened Aug 1, 2026
[Bug] ColorPage sample snippet still teaches a raw PUA glyph with no `.FontFamily` — the class #999 fixed has no gate Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 52/100

microsoft/microsoft-ui-reactor#1019 · Opened Jul 31, 2026
[Feature] Add the reverse pool-reset invariant: a `poolReset: true` modifier must be cleared on every receiver its gate admits Open

enhancement needs-triage

microsoft/microsoft-ui-reactor#1017 · 8 comments · 1 assignee · Opened Jul 31, 2026
`PreviewCaptureServer` can serve a stale frame after `/preview` switches components Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#1014 · Opened Jul 31, 2026
[Bug] ElementPool.CleanElement never releases Control.HorizontalContentAlignment / VerticalContentAlignment Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 52/100

microsoft/microsoft-ui-reactor#1013 · Opened Jul 31, 2026
REACTOR_A11Y_003 doesn't accept fluent .Header(...) as a label, and doesn't cover ComboBox/ToggleSwitch Open

accessibility analyzer

Difficulty 4/5 3-5 days Newbie friendliness 55/100

microsoft/microsoft-ui-reactor#1007 · Opened Jul 31, 2026
[Bug] RichTextBlock.Foreground has no ThemeRef overload, so .Foreground(Theme.X) is silently dropped Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 68/100

microsoft/microsoft-ui-reactor#1002 · Opened Jul 31, 2026
[Bug] Transform modifiers (Scale/Rotation/Translation/CenterPoint) have no unset arm — and ClearValue alone can't undo an animated write Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 58/100

microsoft/microsoft-ui-reactor#1001 · Opened Jul 31, 2026
[Flaky test] Two selftest fixtures still throw on a missing precondition, truncating TAP and hiding every later check Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 76/100

microsoft/microsoft-ui-reactor#998 · 3 comments · Opened Jul 31, 2026
[Flaky test] OverlayLifecycle_Expire_* races on an 80ms margin — and 2 of the file's 4 delays cannot be converted to WaitFor Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#995 · Opened Jul 31, 2026
[Flaky] LT_Unmounts_Exactly_30 / LT_NoLeak_MountsEqualUnmounts — real unmount-accounting deficit, not the #988 watchdog Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/microsoft-ui-reactor#994 · 4 comments · Opened Jul 31, 2026
[Bug] Issue487_SV2* fail deterministically on non-interactive sessions — InteractionTracker completes scrolls without moving Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 68/100

microsoft/microsoft-ui-reactor#990 · 13 comments · Opened Jul 31, 2026
spec 044 audit: all eight cited migration commit SHAs are dangling Open

documentation

Difficulty 3/5 1-2 days Newbie friendliness 68/100

microsoft/microsoft-ui-reactor#975 · Opened Jul 31, 2026
Padding/Margin reconciler + pool gaps found while fixing #950 (dead Margin reset, stale inline edges, Control pool leak) Open

bug

Difficulty 5/5 Over a week Newbie friendliness 45/100

microsoft/microsoft-ui-reactor#965 · 6 comments · Opened Jul 31, 2026
Enforce the FlyoutBase.Placement choke point with an internal analyzer instead of a syntactic test scan Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/microsoft-ui-reactor#964 · Opened Jul 31, 2026
[Bug] ContentDialog.IsOpen and Flyout.IsOpen have no falling edge — declaring IsOpen = false never closes them Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/microsoft-ui-reactor#948 · Opened Jul 30, 2026
Flyout / MenuFlyout / CommandBarFlyout silently disable their target's own callbacks Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

microsoft/microsoft-ui-reactor#942 · Opened Jul 29, 2026
[Flaky] WindowLevel_RuntimeFlip_Topmost fails intermittently in the full selftest run Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

microsoft/microsoft-ui-reactor#927 · 2 comments · Opened Jul 28, 2026
Discussion: normalized transform-origin ergonomics for declarative transforms Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/microsoft-ui-reactor#773 · Opened Jul 1, 2026
Harden RichTextBlock reactive scroll-anchor (#649 follow-up): clamp-filter intent refresh, unbounded armed state, restore/nested-host coverage Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/microsoft-ui-reactor#718 · 1 comment · Opened Jun 26, 2026

A short digest of beginner-friendly GitHub issues.