[Windows] Fix for Shell.FlyoutVerticalScrollMode="Disabled" does not disable scrolling

[HarishwaranVijayakumar]

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

• When Shell.FlyoutVerticalScrollMode is set to "Disabled", the flyout items should not allow vertical scrolling. However, on Windows, the flyout still scrolls even when the mode is set to "Disabled".

Root Cause of the issue

• Although UpdateValue(nameof(Shell.FlyoutVerticalScrollMode)) is called in the OnPaneOpening event, the MapFlyoutVerticalScrollMode method is never executed because the property is not registered in the PropertyMapper, which prevents the scroll mode from being disabled.

Description of Change

• Added mapping for the Shell.FlyoutVerticalScrollMode property in the handler property map to enable platform-specific updates.
• Ensured that the flyout vertical scroll mode is updated when the Shell is loaded on Windows by calling UpdateValue(nameof(Shell.FlyoutVerticalScrollMode)) in OnLoaded.

Issues Fixed

Fixes #32416

Tested the behaviour in the following platforms

• - Window
• - Android
• - iOS
• - Mac

Output

Before	After
Before_fix.mp4	After_fix.mp4

[sheiksyedm]

/azp run

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[sheiksyedm]

/azp run

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Azure Pipelines successfully started running 3 pipeline(s).

[Copilot]

Pull Request Overview

This PR fixes a Windows-specific bug where setting Shell.FlyoutVerticalScrollMode="Disabled" does not actually disable vertical scrolling in the flyout menu. The fix adds the missing property mapping and ensures the scroll mode is updated when the Shell loads.

Key Changes

• Added FlyoutVerticalScrollMode to the Shell handler property mapper for Windows
• Added UpdateValue call for FlyoutVerticalScrollMode in the OnLoaded event handler
• Created UI test with HostApp page and test case to verify the fix

Reviewed Changes

Copilot reviewed 4 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
ShellHandler.cs	Adds FlyoutVerticalScrollMode to Windows-specific property mapper
ShellHandler.Windows.cs	Calls UpdateValue for FlyoutVerticalScrollMode on Shell load
Issue32416.cs (HostApp)	Test page demonstrating disabled scroll mode with 20 menu items
Issue32416.cs (Tests)	NUnit test that scrolls and verifies via screenshot
VerifyFlyoutVerticalScrollModeDisabled.png (3 files)	Platform-specific screenshot baselines

[Copilot]

MenuItem elements are missing AutomationId attributes required for UI test automation. According to the UI Testing Guidelines, all interactive controls must have AutomationId for reliable test automation. Update each MenuItem to include AutomationId like this: AutomationId = $\"Item {i}\". Example of proper usage exists in the codebase at ShellBackButtonBehavior.cs line 21: Items.Add(new MenuItem() { Text = \"Flyout Open\", AutomationId = \"Flyout Open\" });

[sheiksyedm]

/azp run

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Azure Pipelines successfully started running 3 pipeline(s).

[MauiBot]

🤖 AI Summary

📊 Expand Full Review — a0178c1 · Added pending snapshot

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🔍 Pre-Flight — Context & Validation

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Issue: #32416 - [Android, Windows] Shell.FlyoutVerticalScrollMode="Disabled" does not disable scrolling
PR: #32516 - [Windows] Fix for Shell.FlyoutVerticalScrollMode="Disabled" does not disable scrolling
Platforms Affected: Android, Windows (PR implementation targets Windows)
Files Changed: 2 implementation, 2 test code, 3 snapshot baselines

Key Findings

• Issue [Android, Windows] Shell.FlyoutVerticalScrollMode="Disabled" does not disable scrolling #32416 reports the bug on Android and Windows, but this PR changes only Windows Shell handler code.
• The implementation change is limited to Shell handler mapping on Windows: adding Shell.FlyoutVerticalScrollMode to the property mapper and updating the value during OnLoaded.
• Test coverage was added as a UI test pair: src/Controls/tests/TestCases.HostApp/Issues/Issue32416.cs and src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32416.cs, plus new snapshot baselines.
• Inline review feedback notes that the HostApp MenuItem instances do not set AutomationId, while the UI test currently waits for text-based element discovery using "Item 1".
• No prior PRAgent review output was found in PR comments; only pipeline trigger comments and a Copilot summary/review thread are present.

Edge Cases / Discussion Notes

• The issue report specifically reproduces the bug with many MenuItem entries added to the flyout, which creates enough content to scroll.
• A maintainer comment confirms repro on Android and Windows in multiple MAUI versions.
• The PR description says the bug is Windows-specific even though screenshot baselines were added for iOS and Mac test assets.

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #32516	Register Shell.FlyoutVerticalScrollMode in the Shell handler mapper and trigger a Windows update on OnLoaded; add a UI screenshot test for a locked flyout with many menu items.	PENDING (Gate)	src/Controls/src/Core/Handlers/Shell/ShellHandler.cs, src/Controls/src/Core/Handlers/Shell/ShellHandler.Windows.cs, src/Controls/tests/TestCases.HostApp/Issues/Issue32416.cs, src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32416.cs	Original PR

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🚦 Gate — Test Verification

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Gate Result: PASSED

Result: PASSED

Platform: windows
Mode: Full Verification

• Tests FAIL without fix:
• Tests PASS with fix:

Evidence

• Verification used the required verify-tests-fail-without-fix skill via task agent.
• Broken-baseline run failed Issue32416.VerifyFlyoutVerticalScrollModeDisabled with a visual snapshot mismatch (~2.98% difference), proving the test catches the regression.
• Restored-fix run passed the same test (1/1 passing), proving the PR fix satisfies the verification gate on Windows.

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🔧 Fix — Analysis & Comparison

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Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
1	try-fix	Bypass the mapper on Windows by applying FlyoutVerticalScrollMode directly from ShellHandler.Windows.cs during template/pane events and PropertyChanged.	PASS	1 file	Works, but adds custom Windows-only property-change plumbing instead of using the standard mapper flow.
2	try-fix	Keep the mapper entry, but apply UpdateValue(nameof(Shell.FlyoutVerticalScrollMode)) from OnApplyTemplateFinished instead of OnLoaded.	PASS	2 files	Viable and precise, but not clearly better than the PRs reuse of the existing OnLoaded initialization path.
3	try-fix	Call MapFlyoutVerticalScrollMode(this, VirtualView) directly during OnPaneOpening only, without adding a mapper entry.	FAIL	1 file	Repeated Windows runs still showed visual diffs; pane-opening alone is insufficient.
4	try-fix	Override UpdateValue(string? property) in ShellHandler.Windows.cs to manually dispatch MapFlyoutVerticalScrollMode for initial and runtime updates.	PASS	2 files	Functional, but introduces a Windows public API change and PublicAPI maintenance cost.
5	try-fix	Cache the desired flyout scroll mode on MauiNavigationView and apply it inside OnApplyTemplate() when the ScrollViewer exists.	PASS	3 files	Strong root-cause alternative, but broader than necessary because it adds control-side state.
6	try-fix	Set ScrollViewer.VerticalScrollMode on the MauiNavigationView root and rely on WinUI inheritance to reach the internal flyout scroll viewer.	FAIL	2 files	WinUI inheritance did not affect the internal scroll viewer.
7	try-fix	Suppress scroll input on the internal MenuItemsScrollViewer via wheel/view-changing event handlers.	FAIL	2 files	The saved test log still failed the screenshot assertion, so this cannot count as a pass.
8	try-fix	If the ScrollViewer is missing, defer application via LayoutUpdated, then apply once and unsubscribe.	PASS	2 files	Works, but adds event-subscription timing logic that is more complex than the PRs OnLoaded approach.
PR	PR #32516	Register Shell.FlyoutVerticalScrollMode in the shared Shell mapper and trigger a Windows update on OnLoaded.	PASSED (Gate)	4 code files + snapshots	Original PR; minimal change that aligns with existing Windows handler initialization.

Cross-Pollination

Model	Round	New Ideas?	Details
claude-opus-4.6	1	Yes	Direct Windows-only application path that bypasses the mapper.
claude-sonnet-4.6	1	Yes	Use the shared mapper, but apply from OnApplyTemplateFinished instead of OnLoaded.
gpt-5.3-codex	1	Yes	Try direct pane-opening application only; empirically failed.
gemini-3-pro-preview	1	Yes	Override UpdateValue on Windows to manually route this property to the mapper.
claude-opus-4.6	2	No	NO NEW IDEAS
claude-sonnet-4.6	2	Yes	Move timing responsibility into MauiNavigationView via cached scroll mode applied during template creation.
gpt-5.3-codex	2	No	NO NEW IDEAS
gemini-3-pro-preview	2	No	NO NEW IDEAS
claude-opus-4.6	3	Yes	Suppress wheel/gesture scrolling directly on the internal ScrollViewer.
claude-sonnet-4.6	3	No	NO NEW IDEAS
gpt-5.3-codex	3	No	NO NEW IDEAS
gemini-3-pro-preview	3	Yes	Defer application through LayoutUpdated until the internal ScrollViewer exists.

Exhausted: Yes
Selected Fix: PR #32516 It passes the gate, stays within existing handler patterns, avoids public API expansion, and is simpler/less invasive than the passing alternatives.

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📋 Report — Final Recommendation

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Final Recommendation: APPROVE

Phase Status

Phase	Status	Notes
Pre-Flight	COMPLETE	Issue/PR context gathered; bug is Android+Windows, PR change is Windows-only.
Gate	PASSED	Windows full verification proved the test fails without the fix and passes with it.
Try-Fix	COMPLETE	8 attempts explored across 3 cross-pollination rounds; multiple alternatives passed, but PR fix remained the best tradeoff.
Report	COMPLETE

Summary

PR #32516 fixes the Windows Shell flyout scrolling bug by wiring Shell.FlyoutVerticalScrollMode into the existing Shell property mapper and reapplying it during the Windows handler initialization path. The gate passed on Windows: the new test failed against the broken baseline and passed with the PR fix.

The mandatory try-fix exploration found several working alternatives, but each was less attractive than the PR for at least one reason: extra Windows-only plumbing, broader control-side state changes, added event timing complexity, or a public API change. The PR's implementation is the smallest change that preserves the normal mapper-based design and solves the verified scenario.

Root Cause

The Windows flyout scroll mode property was not registered in the Shell handler mapper, so UpdateValue(nameof(Shell.FlyoutVerticalScrollMode)) was a no-op. In practice, the disabled scroll mode needed both mapper participation and a post-template reapplication point so the internal flyout ScrollViewer actually received the setting.

Fix Quality

The PR addresses the missing mapper registration and uses an existing Windows initialization hook (OnLoaded) to reapply the value once the platform view is ready. That keeps the fix local, avoids introducing new public API surface, and aligns with the existing pattern already used in OnLoaded for other flyout-related properties.

A non-blocking note from inline review remains: the added HostApp test page uses menu item text lookup instead of explicit AutomationId values. Gate verification showed the test works today, so this is not blocking the recommendation.

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