Fix for NavigationPage.TitleView does not expand with host window in iPadOS 26+

[SuthiYuvaraj]

Issue Description:

On iPadOS 26+, NavigationPage.TitleView does not resize when the window dimensions change during device rotation, causing the TitleView to remain at its original width instead of expanding to fill the navigation bar.

Root Cause

iOS 26+ changed UIKit's layout behavior so that NavigationItem.TitleView container frames are no longer automatically updated during ViewWillTransitionToSize transitions, causing the TitleView to retain its original dimensions even when the navigation bar resizes.

Description of Change

Added explicit frame updates for the TitleView Container during view controller transitions on iOS 26+ by leveraging AnimateAlongsideTransition to synchronize the Container's frame with the navigation bar's dimensions, ensuring smooth resizing during rotation and window size changes.

Issues Fixed

Fixes #32722

Tested the behaviour on the following platforms

• Android
• Windows
• iOS
• Mac

Note:

This PR extends the behavior introduced in #32815 by adding support for the iPad scenario. As the earlier PR already provided the necessary test coverage, no new testcases are included in this follow‑up.

Output Screenshot

Before Issue Fix	After Issue Fix
Screen.Recording.2025-12-10.at.5.34.39.PM.mov	Screen.Recording.2025-12-10.at.5.32.12.PM.mov

[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 -- 33088

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 33088"

[Copilot]

Pull request overview

This PR fixes a layout issue on iPadOS 26+ where NavigationPage.TitleView does not resize when window dimensions change during device rotation or Stage Manager window resizing. The fix adds explicit frame updates during view controller transitions to work around iOS 26+ layout behavior changes.

Key Changes:

• Added frame update logic in ViewWillTransitionToSize that synchronizes the TitleView Container's frame with the navigation bar during transitions
• Uses AnimateAlongsideTransition to ensure smooth resizing alongside the system animation
• Fix is scoped to iPad devices running iOS/MacCatalyst 26+

[sheiksyedm]

/rebase

[rmarinho]

🤖 AI Summary

📊 Expand Full Review

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🔍 Pre-Flight — Context & Validation

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📝 Review Session — Update NavigationRenderer.cs · 9d67ddf

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Issue: #32722 - NavigationPage.TitleView does not expand with host window in iPadOS 26+

PR: #33088 by @SuthiYuvaraj

Platforms Affected: iOS (specifically iPadOS 26+, MacCatalyst 26+)

Files Changed: 1 implementation file (no new test files - tests from related PR #32815 reused)

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Summary

On iPadOS 26+, NavigationPage.TitleView does not resize when window dimensions change during Stage Manager window resizing or multitasking. The TitleView remains at its original width instead of expanding to fill the navigation bar.

Root Cause (from PR)

iOS 26+ changed UIKit's layout behavior so that NavigationItem.TitleView container frames are no longer automatically updated during ViewWillTransitionToSize transitions, causing the TitleView to retain its original dimensions even when the navigation bar resizes.

PR's Fix Approach

Added explicit frame updates for the TitleView Container during view controller transitions on iOS 26+ by leveraging AnimateAlongsideTransition to synchronize the Container's frame with the navigation bar's dimensions in ViewWillTransitionToSize.

Implementation:

• In ViewWillTransitionToSize method of NavigationRenderer.cs (nested ViewController class)
• For iPad devices (UIUserInterfaceIdiom.Pad) on iOS/MacCatalyst 26+
• Calls UpdateTitleViewFrameForOrientation() within AnimateAlongsideTransition
• 16 lines added (XML doc + fix code)

Related Context

• Related PR [iOS 26] NavigationPage.TitleView resizing on iOS 26+ rotation - Fix #32815: Earlier fix for iPhone rotation scenario via TraitCollectionDidChange - provided test coverage
• PR Fix for NavigationPage.TitleView does not expand with host window in iPadOS 26+ #33088: Extends [iOS 26] NavigationPage.TitleView resizing on iOS 26+ rotation - Fix #32815 to support iPad Stage Manager window resizing via ViewWillTransitionToSize
• No new tests: PR states tests from [iOS 26] NavigationPage.TitleView resizing on iOS 26+ rotation - Fix #32815 provide necessary coverage
• Test file: Issue32722.cs exists and tests TitleView expansion on rotation via SetOrientationLandscape()

Key Findings

• Issue is specific to iOS 26+ behavior change in UIKit
• Affects iPad devices (Stage Manager window resizing)
• Tests exist from PR [iOS 26] NavigationPage.TitleView resizing on iOS 26+ rotation - Fix #32815 (Issue32722.xaml/cs)
• Fix is minimal and scoped to iPad iOS 26+ in ViewWillTransitionToSize
• Latest commit (2026-02-17) added XML documentation to ViewWillTransitionToSize and updated code comment
• No new tests were added in any PR commits

Prior Agent Review Found

• Previous FAILED (tests pass both with and without fix)Gate:
• Previous REQUEST CHANGES (test coverage inadequate)Report:
• Note: Tests use SetOrientationLandscape() which tests TraitCollectionDidChange path (from PR [iOS 26] NavigationPage.TitleView resizing on iOS 26+ rotation - Fix #32815), NOT the ViewWillTransitionToSize path added by this PR

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #33088	Add AnimateAlongsideTransition with UpdateTitleViewFrameForOrientation() in ViewWillTransitionToSize for iPad on iOS PENDING (Gate)	NavigationRenderer.cs (+16)	Original PR - extends #32815 for iPad Stage Manager	26+

Discussion Summary

PR Comments:

• Automated dogfood instructions
• Rebase request from maintainer
• Prior agent review found Gate failure (tests don't catch bug)
• Copilot review: confirmed fix scopes properly to iPad iOS 26+
• Copilot review: suggested enhancing code comment (PR author incorporated suggestion in latest commit)

Issue Comments:

• Validated on iOS 26.0 (regression from iOS 18.0)
• User asking for timeline on fix release

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🚦 Gate — Test Verification

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📝 Review Session — Update NavigationRenderer.cs · 9d67ddf

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** FAILEDResult:**

Platform: iOS

Mode: Full Verification

Issue: Tests pass both WITH and WITHOUT the fix, indicating they don't properly reproduce the bug.

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Test Behavior

• Tests FAIL without NO (tests unexpectedly PASSED)fix:
• Tests PASS with fix YES:

Problem Analysis

The test Issue32722.cs uses App.SetOrientationLandscape() (device rotation) to test TitleView resizing. However:

this was fixed in PR #32815
this is what PR #33088 fixes

The test exercises TraitCollectionDidChange (already fixed in #32815), NOT ViewWillTransitionToSize (the new code in this PR). This is why the test passes even without the PR's fix.

Second Gate Failure

This is the second consecutive Gate failure for this PR. The previous agent review (from prior commit 072ef67) also found the same issue. The most recent commit (9d67ddf from 2026-02-17) only added XML documentation and a code comment update to NavigationRenderer. no tests were added or modified.cs

What's Needed

A new test (or updated test) that:

1. Navigates to Issue32722NavPage
2. Triggers ViewWillTransitionToSize (window resizing, not rotation)
3. Verifies TitleView expands to fill the new width
4. This test should FAIL without the PR's AnimateAlongsideTransition code

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🔧 Fix — Analysis & Comparison

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📝 Review Session — Update NavigationRenderer.cs · 9d67ddf

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Fix Phase Skipped

Phase 3 (Fix) was skipped because Gate must pass before Fix exploration.FAILED Gate

When Gate fails, it means the existing tests don't catch the bug, so try-fix cannot be run reliably (the test framework needs working tests to evaluate fix candidates).

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #33088	Add with in	PASS (Gate)	NavigationRenderer.cs (+16)	Gate passed with fix, but Gate FAILED overall (tests pass without fix too)

Exhausted: N/A (Gate failed - Fix phase skipped)

Selected Fix: PR's fix - The implementation is correct, but test coverage must be added first before a proper evaluation can be completed.

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📋 Report — Final Recommendation

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📝 Review Session — Update NavigationRenderer.cs · 9d67ddf

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Final Recommendation: REQUEST CHANGES##

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Executive Summary

PR #33088 adds a well-scoped, minimal fix for iPadOS 26+ Stage Manager TitleView resizing. The implementation quality is excellent. However, the Gate failed for the second consecutive existing tests do not verify the bug this PR fixes, and the PR has no new tests.time

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Gate FAILED (2nd failure)Outcome:

Platform tested: iOS

Issue: Tests pass both WITH and WITHOUT the fix.

Root Cause of Gate Failure:

The test Issue32722.cs uses SetOrientationLandscape() (device rotation), which exercises the TraitCollectionDidChange code path fixed in PR # not the ViewWillTransitionToSize code path added in this PR #33088.32815

User Action	Code Path	Fixed In
Device rotation		PR #32815
Stage Manager window resize	ViewWillTransitionToSize	PR # this PR

The test only validates rotation behavior. The window-resizing behavior (the actual bug this PR fixes) is not tested.

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Code Quality Excellent:

The implementation is clean and minimal:

• Correctly scoped to iPad devices only (UIUserInterfaceIdiom.Pad)
• Properly version-gated to iOS/MacCatalyst 26+
• Reuses existing UpdateTitleViewFrameForOrientation() method
• Uses correct UIKit animation pattern (AnimateAlongsideTransition)
• Includes XML documentation and explanatory comment

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Change Needed: Tests Must Be Added

A test that properly exercises ViewWillTransitionToSize is required. Suggested approaches:

1. Update Issue32722.cs to directly test ViewWillTransitionToSize behavior using window resize APIs
2. Add a new test specifically for the Stage Manager scenario

The test must:

• FAIL without the AnimateAlongsideTransition code in ViewWillTransitionToSize
• PASS with the fix applied

The write-tests-agent can help create appropriate tests.

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History

• Previous review (commit 072ef67): FAILED, REQUEST CHANGESGate
• Latest commit (9d67ddf, 2026-02-17): Only added XML documentation and code no new testscomment
• This review: FAILED again for the same reasonGate

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📋 Expand PR Finalization Review

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Title: ⚠️ Needs Update

Current: Fix for NavigationPage.TitleView does not expand with host window in iPadOS 26+

Issues:

• Verbose and conversational ("Fix for ... does not ...")
• Doesn't follow the standard [Platform] Component: What changed pattern
• Missing platform prefix

Recommended: [iOS] NavigationPage: Fix TitleView not expanding on window resize (iPadOS/MacCatalyst 26+)

Description: ✅ Good

• Verbose and conversational ("Fix for ... does not ...")
• Doesn't follow the standard [Platform] Component: What changed pattern
• Missing platform prefix

✨ Suggested PR Description

[!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 Description

On iPadOS 26+, NavigationPage.TitleView does not resize when the window dimensions change during Stage Manager window resizing or multitasking, causing the TitleView to remain at its original width instead of expanding to fill the navigation bar.

Root Cause

iOS 26+ changed UIKit's layout behavior so that NavigationItem.TitleView container frames are no longer automatically updated during ViewWillTransitionToSize transitions. This specifically affects iPad Stage Manager window resizing and multitasking scenarios, where the window size changes without a device rotation.

Context: PR #32815 previously fixed the device-rotation scenario by handling TraitCollectionDidChange. This PR extends that fix to cover window-resize transitions via ViewWillTransitionToSize.

Description of Change

In ViewWillTransitionToSize in NavigationRenderer.cs (nested ChildViewController), added an AnimateAlongsideTransition call for iPad devices on iOS/MacCatalyst 26+ that invokes the existing UpdateTitleViewFrameForOrientation() method. This synchronizes the TitleView container frame update with UIKit's transition animation, ensuring the TitleView expands to fill the navigation bar after a window resize.

This complements the TraitCollectionDidChange handling added in #32815:

Scenario	Code Path	Fixed In
Device rotation	TraitCollectionDidChange	PR #32815
Stage Manager window resize / multitasking	ViewWillTransitionToSize	This PR (#33088)

Issues Fixed

Fixes #32722

Tested the behaviour on the following platforms

• Android
• Windows
• iOS (iPad Stage Manager window resizing)
• Mac

Note

This PR extends the behavior introduced in #32815 by adding support for the iPad Stage Manager window resizing scenario. The earlier PR already provided test coverage for TitleView resizing via Issue32722.cs (rotation test); no new test cases are included in this follow-up.

Code Review: ✅ Passed

Code Review Findings — PR #33088

File: src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs

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✅ No Critical Issues

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✅ Looks Good

1. Correct version guard

if (OperatingSystem.IsIOSVersionAtLeast(26) || OperatingSystem.IsMacCatalystVersionAtLeast(26))

Both iOS and MacCatalyst variants are checked, which is important because .ios.cs files compile for both platforms.

2. Correct UIKit animation pattern

coordinator.AnimateAlongsideTransition is the right API to synchronize custom frame updates with UIKit's own transition animation. Using it ensures smooth, glitch-free resizing.

3. Properly scoped to iPad only

The new code is nested inside the existing UIUserInterfaceIdiom.Pad check — iPhones are unaffected.

4. Excellent reuse of UpdateTitleViewFrameForOrientation()

No logic is duplicated; the exact same method used in TraitCollectionDidChange (for rotation) is reused here (for window resize). This is the correct pattern.

5. XML doc comment added

The override now has a <summary> that explains the iOS 26+ iPad-specific behavior. Good addition.

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🟡 Low-Priority Suggestions

1. XML doc comment could mention MacCatalyst

File: NavigationRenderer.cs:1605–1608

The <summary> says "iPad iOS 26+" but the code also applies to MacCatalyst 26+ (via IsMacCatalystVersionAtLeast(26)). Minor nit.

Current:

/// On iPad iOS 26+, manually updates TitleView frame to handle Stage Manager window resizing.

Suggested:

/// On iPad iOS/MacCatalyst 26+, manually updates TitleView frame to handle Stage Manager window resizing.

2. Test coverage gap (informational — pre-existing, not introduced by this PR)

The existing test Issue32722.cs uses App.SetOrientationLandscape() (device rotation), which exercises the TraitCollectionDidChange code path from PR #32815 — not the ViewWillTransitionToSize path added by this PR. There is no automated test that verifies Stage Manager window-resize behavior.

Prior agent review flagged this as a Gate failure (tests pass with and without the fix). Whether this is acceptable depends on whether Stage Manager window-resize can be simulated in Appium tests.

This is informational only — the author acknowledged no new tests were added, and Stage Manager resize may not be automatable in the current test infrastructure.

3. Thread.Sleep(2000) in test (pre-existing, not introduced by this PR)

File: src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32722.cs:29, 47

The test uses System.Threading.Thread.Sleep(2000) after SetOrientationLandscape/Portrait. Per testing guidelines, VerifyScreenshot(retryTimeout: ...) or App.WaitForElement with a timeout is preferred. This was introduced in PR #32815, not here.

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Summary

Criterion	Result
Correctness	✅ Correct UIKit API, correct version guard, correct device scope
Code quality	✅ Clean, minimal, well-documented
Reuse	✅ Reuses UpdateTitleViewFrameForOrientation() — no duplication
Breaking changes	✅ None — only affects iPad iOS/MacCatalyst 26+
Platform scope	✅ Properly limited to UIUserInterfaceIdiom.Pad
Test coverage	⚠️ No test for the new code path (Stage Manager resize) — pre-existing concern

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