[devanathan-vaithiyanathan]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Issue Details:

On Windows, the application crashes when multiple CollectionView controls share the same ObservableCollection and one of the views is hidden.
The issue can be reproduced by binding two CollectionView controls to the same ObservableCollection, setting IsVisible to false on one of them, and then adding a new item to the collection.

Root Cause:

Collection changes trigger automatic scrolling. A collapsed WinUI view can still report IsLoaded == true without having its internal item presenter created. The previous loaded-state check therefore allowed an invalid native scroll request.

Description of Changes:

Skip scrolling related logic when the native view is collapsed

Issues Fixed

Fixes #39751

Tested the behavior in the following platforms.

• Android
• Windows
• iOS
• Mac

Before	After
Windows Before-39751.mp4	Windows After-39751.mp4

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 39760

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 39760"

[github-actions]

Expert Review — 1 finding

Reviewed commit bf5052d.

See inline comments for details.

[github-actions]

[moderate] Regression Prevention and Test Coverage - The visible CollectionView does not provide a discriminating negative test for the new visibility guard: its only assertions compare ItemsSource contents, which are updated independently of ApplyItemsUpdatingScrollMode. The reveal assertions likewise check loaded labels rather than scrolling, and the fixture starts with only three 40px rows in a 200px viewport. Returning unconditionally from ApplyItemsUpdatingScrollMode would still satisfy these assertions, while breaking automatic scrolling for visible views. Add an overflowing visible-view case and assert the resulting scroll position for both modes (starting away from the first item for KeepItemsInView), so the test proves that visible updates are not suppressed along with hidden ones.

[github-actions]

Tests Failure Analysis

@devanathan-vaithiyanathan — test-failure analysis for commit bf5052d.

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🧪 CI Analysis — click to expand

📊 maui-pr

No failures found.

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🧪 maui-pr-devicetests

• 🟡 Needs human investigation — InteractivePopGesture: 24 renderer-type assertions, MacCatalyst CoreCLR / iOS Mono/CoreCLR; target history lacks comparable assertions/parameters.
• 🟡 Needs human investigation — ResetRestoresNativeAppearance: 12 false assertions, MacCatalyst / iOS; both tint variants lack reason-complete target evidence.
• 🟡 Needs human investigation — Android Mono InvokeDotNet: 25-second HybridWebView readiness timeout plus crash evidence; no matching target diagnostic.
• 🟡 Needs human investigation — Two MacCatalyst crash-marked work items (macOS 15, 26); iOS Mono termination also needs completion verification. Inspect termination diagnostics, not wrapper exit codes.

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🧪 maui-pr-uitests

• 🟡 Needs human investigation — Windows spacing / selection: identical 4.58%/5.84% differences on target, but handler equivalence is unverified.
• 🟡 Needs human investigation — Windows CV1: three missing snapshots, not pixel differences; check baseline packaging. This PR adds no UI snapshots.
• 🟢 Likely unrelated — Windows Search text color and Shell flyout: exact 0.70%/7.79% failures recur on target; these expectations are unchanged.
• 🟢 Likely unrelated — Android HybridWebView shadow/RTL, SafeArea, flyout ×2: identical target image diagnostics; Windows-only changes cannot alter Android execution.
• 🟢 Likely unrelated — Two Android picker-selection snapshots: exact target matches, unlike the other 22 comparisons.
• 🟢 Likely unrelated — iOS edge-swipe assertion/timeout, Shell colors, background/flyout: same target reasons; Apple behavior is unchanged.
• 🟢 Likely unrelated — MacCatalyst gradient reset: same 0.66% target mismatch; Windows-only change.
• 🟡 Needs human investigation — Android Material3: 22 picker mismatches, tab-overflow mismatch, Shell height mismatch (2737→2796); compare equivalent API-36 captures.
• 🟡 Needs human investigation — iOS floating-tab content: 1.66% mismatch lacks an equivalent target diagnostic.
• 🟡 Needs human investigation — MacCatalyst Shell2: 22 captures changed 789×563→1920×1051; check window sizing. 17 percentage-parser failures obscure separate image diagnostics.
• 🟡 Needs human investigation — MacCatalyst menus: 11 Appium 45-second timeouts; Search text returns “Search”; disabled menu reports “Failure”. No reason-matched target results.
• 🟡 Needs human investigation — MacCatalyst recovery and input transparency time out; flyout differs by 6.97%, unlike other platforms.
• 🟡 Needs human investigation — Log-only Android CheckIsEnabled / Material3 dialog have element timeouts; Material3 button reports possible app exit. Retrieve full results.
• 🟡 Needs human investigation — Log-only MacCatalyst navigation: element/Appium timeouts; three SearchHandler icon tests: visual failures. Target diagnostics are insufficient.
• Insufficient data — UI collection is truncated (100/151 failure rows); all five target samples are partial. Restore omitted diagnostics.

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🧭 Follow-up — actions and refresh

Next action: Restore evidence; inspect device termination and CV1 snapshot packaging. Do not duplicate existing runs.

Maintainers: comment /review tests to refresh this report.

[Copilot]

🔵 Needs a closer look

Windows runtime validation remains necessary because deferred scroll callbacks recheck only IsLoaded after visibility may change, and the added device tests were not executed.

No open issues 🎉

What changed in this PR

Addresses #39751, a .NET 11 Windows CollectionView regression where updating a shared ObservableCollection can crash when one bound view is hidden. The fix guards automatic scrolling in the Items2 handler.

Changes:

• Skip item-update scrolling when the native view is collapsed, even if it reports being loaded.
• Add Windows device tests covering shared-source updates, visibility transitions, collection mutations, and both supported automatic-scroll modes.

File	Description
src/​Controls/​tests/​DeviceTests/​Elements/​CollectionView/​CollectionViewTests.Windows.cs	Adds regression coverage for visible and hidden CollectionViews sharing a collection.
src/​Controls/​src/​Core/​Handlers/​Items2/​ItemsViewHandler2.Windows.cs	Adds a native visibility check before automatic scrolling.

_{Review effort: Balanced}

[MauiBot]

PR Test Gate

@devanathan-vaithiyanathan — existing-test verification for commit bf5052d9.

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🧪 Gate analysis — click to expand

✅ Passed. The selected verification satisfied the gate's passing conditions. Unmatched, skipped, or inconclusive groups are not passing evidence.

📱 Device tests

Test group	Without fix	With fix
CollectionViewTests (CollectionView2SharedItemsSourceUpdatesWhileHidden)	✅ Failed as expected (837s)	✅ Passed (205s)

Execution log excerpts

Without fix CollectionViewTests (CollectionView2SharedItemsSourceUpdatesWhileHidden)

WINDOWS_DEVICE_TEST_NO_RESULTS: Windows device test result file 'D:\a\1\s\CustomAgentLogsTmp\PRState\39760\PRAgent\gate\verify-tests-fail\test-without-fix-CollectionViewTests__CollectionView2SharedItemsSourceUpdates.log.diagnostics\TestResults-Microsoft_Maui_Controls_DeviceTests_CollectionView.xml' is empty or not valid XML (the device-test app likely crashed or exited before writing results).

With fix CollectionViewTests (CollectionView2SharedItemsSourceUpdatesWhileHidden)

uppress the warning by specifying `x:SuppressXamlTrimWarnings=True` within the closest element. If not, the property path might be trimmed and will not be AOT compatible. [D:\a\1\s\src\Controls\src\Core\Controls.Core.csproj::TargetFramework=net11.0-windows10.0.19041.0]
Platform\Windows\TabbedPage\TabbedPageStyle.xaml(19,21): XamlCompiler warning WMC1510: Ensure the property path is trimming and AOT compatible by making use of 'Compiled Bindings (x:bind)' if possible or by specifying the 'x:DataType' directive with the respective binding data context and marking the type declaration with the 'WinRT.GeneratedBindableCustomProperty' attribute or the 'Microsoft.UI.Xaml.Data.Bindable' attribute. If you are unable to do either but can ensure the data type is attributed correctly, then you can also suppress the warning by specifying `x:SuppressXamlTrimWarnings=True` within the closest element. If not, the property path might be trimmed and will not be AOT compatible. [D:\a\1\s\src\Controls\src\Core\Controls.Core.csproj::TargetFramework=net11.0-windows10.0.19041.0]
    0 Error(s)
Time Elapsed 00:02:25.21
  Passed: 4
  Failed: 0
  Skipped: 0
  Total: 4
  Tests completed successfully

PR head: bf5052d9.

Without-fix baseline: 7de2a9f2.