Fix for Shell tab visibility not updating when navigating back multiple pages

[BagavathiPerumal]

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!

Root cause

The issue occurs because of the navigation sequence used in OnPopToRootAsync() where the platform navigation is triggered before the root page’s lifecycle events are fired. When Shell.Current.GoToAsync("../..") is used, the method InvokeNavigationRequest() executes first, which sends the navigation request to the native platform handlers.

The platform then commits the UI changes immediately. Only after this process, the root page’s OnAppearing() method is called. Since Shell.SetTabBarIsVisible() is typically invoked inside OnAppearing(), it runs too late, after the UI has already been rendered, causing the TabBar visibility change to be ignored.

This timing mismatch does not occur with single-level navigation (GoToAsync("..")) because that flow correctly triggers lifecycle events before the platform navigation begins.

Description of Issue Fix

The fix involves reordering the execution sequence within OnPopToRootAsync() so that PresentedPageAppearing() runs before InvokeNavigationRequest(), ensuring OnAppearing() is triggered early enough for updates such as Shell.SetTabBarIsVisible() to be applied before the platform finalizes the navigation UI.

Additionally, the stack cleanup loop was refined to skip calling SendDisappearing() on the top page since it is already handled by PresentedPageDisappearing(), thereby avoiding duplicate lifecycle events while still notifying intermediate pages. This change aligns multi level pop to root behavior with single level pop, providing consistent lifecycle handling without introducing breaking changes.

Tested the behavior in the following platforms.

• Windows
• Mac
• iOS
• Android

Issues Fixed

Fixes #33351

Output

Before Issue Fix	After Issue Fix
33351-BeforeFix.mov	33351-AfterFix.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.

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Or

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[kubaflo]

🤖 AI Summary

📊 Expand Full Review

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🔍 Pre-Flight — Context & Validation

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📝 Review Session — Fix-33351-Made changes to trigger page appearing events before platform navigation to ensure Shell TabBar visibility is applied correctly during multi-level back navigation. · fb538bf

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Issue: #33351 - Changing Shell Tab Visibility when navigating back multiple pages ignores Shell Tab Visibility
PR: #34403 - Fix for Shell tab visibility not updating when navigating back multiple pages
Platforms Affected: iOS, Android (per issue labels and author testing)
Files Changed: 1 implementation file, 2 test files, 5 snapshot PNG files

Key Findings

Root Cause: Timing mismatch in ShellSection.OnPopToRootAsync(). When GoToAsync("../..") is called, InvokeNavigationRequest() was called first, which synchronously triggers PopToRootViewController on iOS (and equivalent on Android). The platform reads tab-bar state at this moment, committing it to the native navigation. Only after that did PresentedPageAppearing() → OnAppearing() → Shell.SetTabBarIsVisible() fire — too late. This mismatch did not occur with single-level pop (GoToAsync("..")) because OnPopAsync already calls PresentedPageAppearing() before InvokeNavigationRequest().

Fix Approach: Reorder execution in OnPopToRootAsync():

1. PresentedPageDisappearing() fires first (top page disappearing)
2. Reset _navStack
3. PresentedPageAppearing() fires (root page appearing — now has chance to call SetTabBarIsVisible)
4. InvokeNavigationRequest() triggers platform navigation with correct tab-bar state
5. In cleanup loop: skip SendDisappearing on the top page (already handled in step 1); send to intermediate pages only

PR Discussion

Prior Agent Review (PR #34280 → now #34403): A prior agent review exists (visible in PR comments) for commit a222541. This PR (#34403) supersedes PR #34280 and now includes Android snapshot. Labels show s/agent-reviewed, s/agent-approved, s/agent-gate-passed, s/agent-suggestions-implemented — indicating prior review cycle is complete and author implemented suggestions.

Copilot Bot Review Concerns (Current PR #34403):

1. Lifecycle Ordering (ShellSection.cs:875): Intermediate pages receive SendDisappearing AFTER root gets OnAppearing in the new ordering. Copilot suggests firing intermediate SendDisappearing before PresentedPageAppearing()/InvokeNavigationRequest() to match platform-driven lifecycle ordering.
2. Test Host App (Issue33351.cs:42): Tab bar visibility is set in ShellContent.OnAppearing() (via MyTab), but the reported issue scenario involves setting it in the root ContentPage's OnAppearing(). The repro may not exactly match the original issue.
3. Test AutomationId (SharedTests Issue33351.cs:21): Tapping by text "Tab 1" is brittle; prefer AutomationId on the tab.
4. Screenshot Flakiness (SharedTests Issue33351.cs:33): VerifyScreenshot() called without retryTimeout after pop-to-root animation — may have timing issues.

kubaflo approved PR #34403 on head commit fb538bfb (current HEAD).

Edge Cases

• Issue only affects GoToAsync("../..") multi-level pop; single-level pop works correctly
• Fix intentionally fires OnAppearing() before native animation completes (documented with code comment)
• Intermediate pages (page1 in a 3-page stack) now receive OnDisappearing AFTER root's OnAppearing — different from previous behavior

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #34403	Reorder: PresentedPageDisappearing + PresentedPageAppearing before InvokeNavigationRequest; skip top page in cleanup loop	⏳ PENDING (Gate)	ShellSection.cs (+17/-3), Issue33351.cs (HostApp, +167), Issue33351.cs (SharedTests, +34), 5 PNG snapshots	Original PR; prior review approved on iOS

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🚦 Gate — Test Verification

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📝 Review Session — Fix-33351-Made changes to trigger page appearing events before platform navigation to ensure Shell TabBar visibility is applied correctly during multi-level back navigation. · fb538bf

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Result: ✅ PASSED
Platform: android
Mode: Full Verification

• Tests FAIL without fix ✅
• Tests PASS with fix ✅

Test: Issue33351.TabBarVisibilityAfterMultiLevelPopToRoot
Fix file verified: src/Controls/src/Core/Shell/ShellSection.cs

Note: Minor ADB installation error occurred on first attempt but recovered automatically. Final test result was clean: 1/1 tests passed in 24.31s.

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🔧 Fix — Analysis & Comparison

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📝 Review Session — Fix-33351-Made changes to trigger page appearing events before platform navigation to ensure Shell TabBar visibility is applied correctly during multi-level back navigation. · fb538bf

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Fix Candidates

Note: This PR (#34403) is a continuation of PR #34280, which underwent a full 7-attempt try-fix exploration in a prior review session. The fix in ShellSection.cs is identical. Prior findings are imported below.

#	Source	Approach	Test Result	Files Changed	Notes
1	try-fix (prior)	Early if (IsVisibleSection) CurrentItem?.SendAppearing() before InvokeNavigationRequest (minimal 2-line add, keeps PresentedPageAppearing at end)	✅ PASS	ShellSection.cs (+2)	Works but fires appearing twice; simpler than PR
2	try-fix (prior)	Move _navStack reset + PresentedPageAppearing() before InvokeNavigationRequest (mirrors OnPopAsync, no cleanup loop changes)	✅ PASS	ShellSection.cs (+1/-1)	Clean reorder; doesn't handle disappearing side
3	try-fix (prior)	Deferred Dispatcher.Dispatch + synchronous Handler.UpdateValue after PresentedPageAppearing	❌ FAIL	ShellSection.cs (+13)	0.81% snapshot mismatch; post-navigation updates too late
4	try-fix (prior)	Reset _navStack, then InvokeNavigationRequest, then PresentedPageAppearing() before await args.Task	✅ PASS	ShellSection.cs (+1/-1)	Fires appearing after request dispatched but before await
5	try-fix (prior)	PresentedPageDisappearing() + if (IsVisibleSection) CurrentItem?.SendAppearing() before InvokeNavigationRequest	✅ PASS	ShellSection.cs (+3)	Good intermediate approach
6	try-fix (prior)	Synchronous Shell.Current?.Handler?.UpdateValue(TabBarIsVisibleProperty) after navigation and cleanup loop	❌ FAIL	ShellSection.cs (+1)	Same 0.81% mismatch; post-navigation approach fundamentally flawed
7	try-fix (prior)	SendDisappearing on ALL old pages + _navStack[0].SendAppearing() before InvokeNavigationRequest (bypasses Shell machinery)	❌ FAIL	ShellSection.cs (+5/-5)	0.81% mismatch; raw Page.Send* without Shell lifecycle machinery doesn't update tab bar
PR	PR #34403	Full reorder: PresentedPageDisappearing() + PresentedPageAppearing() before InvokeNavigationRequest; add explanatory comment; skip duplicate SendDisappearing on top page in cleanup loop	✅ PASS (Gate)	ShellSection.cs (+17/-3)	Original PR; validated on iOS (prior) AND Android (this session)

Exhausted: Yes (7 attempts from prior review; 4 passed, 3 failed; additional ideas were architectural refactors or variations of failed patterns)

Key Learning: The fix requires Shell lifecycle machinery (PresentedPageAppearing/CurrentItem.SendAppearing) to fire before InvokeNavigationRequest. Post-navigation UpdateValue approaches cannot override already-committed native platform state.

Selected Fix: PR's fix — most complete solution:

1. Correctly handles both disappearing (PresentedPageDisappearing) AND appearing (PresentedPageAppearing) lifecycle in correct order
2. Fixes the duplicate SendDisappearing bug in the cleanup loop
3. Includes explanatory code comment documenting the intentional ordering
4. Aligns multi-level pop behavior with single-level pop (OnPopAsync)
5. Validated on Android (Gate this session) AND iOS (prior review Gate)

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📋 Report — Final Recommendation

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📝 Review Session — Fix-33351-Made changes to trigger page appearing events before platform navigation to ensure Shell TabBar visibility is applied correctly during multi-level back navigation. · fb538bf

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✅ Final Recommendation: APPROVE

Summary

PR #34403 fixes a lifecycle timing bug in ShellSection.OnPopToRootAsync() where Shell.SetTabBarIsVisible() was silently ignored when navigating back multiple levels with GoToAsync("../.."). The fix correctly reorders lifecycle event calls so tab bar state is updated before the platform commits the native navigation. Tests were validated on Android (Gate this session: FAIL without fix / PASS with fix) and iOS (prior review Gate). Seven alternative fix approaches were explored — the PR's solution is the most complete.

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Root Cause

In OnPopToRootAsync(), InvokeNavigationRequest(args) was called first, which synchronously triggers PopToRootViewController (iOS) / equivalent (Android). The platform reads tab-bar visibility at this moment. Only after the platform committed the navigation did PresentedPageAppearing() → OnAppearing() → Shell.SetTabBarIsVisible() fire — too late. This mismatch did not occur with single-level pop (GoToAsync("..")) because OnPopAsync already called PresentedPageAppearing() before InvokeNavigationRequest().

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Fix Quality

The fix is correct and well-implemented:

• Moves PresentedPageDisappearing() and PresentedPageAppearing() before InvokeNavigationRequest()
• Avoids duplicate SendDisappearing on the top page in the cleanup loop
• Includes clear explanatory code comment documenting the intentional ordering
• Aligns multi-level pop behavior with single-level pop (OnPopAsync)

Gate results:

• Android (this session): FAIL without fix ✅ | PASS with fix ✅
• iOS (prior review): FAIL without fix ✅ | PASS with fix ✅

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Code Review Notes (Copilot Bot Observations)

These concerns from the Copilot automated review are worth noting but not blocking:

1. Lifecycle ordering of intermediate pages (ShellSection.cs:875): After the fix, intermediate pages (e.g., Page 1 in a 3-page stack) receive SendDisappearing AFTER the root page has received OnAppearing. This is the reverse of expected lifecycle ordering. The Copilot bot suggests firing SendDisappearing for intermediate pages BEFORE PresentedPageAppearing()/InvokeNavigationRequest(). While this is a valid concern, it only affects apps that interact with intermediate pages' OnDisappearing in lifecycle-ordering-sensitive ways. This is an edge case and could be addressed as a follow-up.

2. Test repro accuracy (Issue33351.cs:42): The test sets tab bar visibility in ShellContent.OnAppearing() (via MyTab) rather than in the root ContentPage.OnAppearing() as described in the original issue. The test still correctly validates the timing fix, but an exact repro of the user-reported scenario would use ContentPage.OnAppearing().

3. AutomationId for tab tap (Issue33351.cs:21): The test taps "Tab 1" by visible text. Adding an explicit AutomationId to the tab would improve test resilience.

4. Screenshot timing (Issue33351.cs:33): VerifyScreenshot() is called without retryTimeout after the pop-to-root animation. This could cause flakiness. Consider VerifyScreenshot(retryTimeout: TimeSpan.FromSeconds(2)).

These are code quality/test robustness suggestions. They do not invalidate the correctness of the fix.

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Comparison with Alternatives (from prior try-fix exploration)

Approach	Result	vs PR
PR's fix (full reorder + duplicate SendDisappearing fix)	✅ PASS	— (baseline)
Minimal: 2-line CurrentItem.SendAppearing() pre-navigation	✅ PASS	Simpler but fires OnAppearing twice
Clean reorder of PresentedPageAppearing only (no disappearing)	✅ PASS	Doesn't handle disappearing side
Post-navigation Dispatcher.Dispatch + UpdateValue	❌ FAIL	Cannot override already-committed native state
InvokeNavigationRequest then PresentedPageAppearing before await	✅ PASS	Weaker ordering guarantee
Bypass Shell machinery with raw Page.Send* calls	❌ FAIL	Shell lifecycle machinery required

The PR's fix is the most complete solution: correctly handles both sides of the lifecycle (disappearing AND appearing) and fixes the incidental duplicate SendDisappearing bug.

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📋 Expand PR Finalization Review

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Title: ✅ Good

Current: Fix for Shell tab visibility not updating when navigating back multiple pages

Description: ✅ Good

Description needs updates. See details below.

✨ 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!

Root Cause

In OnPopToRootAsync(), InvokeNavigationRequest() was called before PresentedPageAppearing(). This meant the platform committed the navigation UI immediately, before the root page's OnAppearing() was ever fired. Any Shell state changes made inside OnAppearing() — such as Shell.SetTabBarIsVisible() — arrived too late to affect the already-rendered navigation.

This timing mismatch only affected multi-level pop (GoToAsync("../..")). Single-level pop (GoToAsync("..")) already followed the correct order: PresentedPageAppearing() first, then InvokeNavigationRequest().

Description of Change

src/Controls/src/Core/Shell/ShellSection.cs

Reordered the execution sequence in OnPopToRootAsync() to match the existing single-level OnPopAsync() lifecycle contract:

Before:

InvokeNavigationRequest(args)   ← platform commits UI immediately
... await completion ...
SendDisappearing() all pages
PresentedPageAppearing()        ← too late, OnAppearing fires after UI is rendered

After:

PresentedPageDisappearing()     ← fire disappearing on top page
PresentedPageAppearing()        ← fire appearing on root page FIRST
InvokeNavigationRequest(args)   ← platform reads updated Shell state when it commits
... await completion ...
SendDisappearing() intermediate pages only (top page already handled)
RemovePage() all pages

The loop cleanup was also refined: SendDisappearing() is now skipped for the top page (index oldStack.Count - 1) since it was already fired by PresentedPageDisappearing() earlier, preventing duplicate lifecycle events on the top page while still notifying all intermediate pages.

Issues Fixed

Fixes #33351

Platforms Tested

• Windows
• Mac
• iOS
• Android

Code Review: ⚠️ Issues Found

Code Review — PR #34403

✅ Looks Good

Core Fix Correctly Aligns with OnPopAsync Pattern

The existing OnPopAsync method already follows this order:

PresentedPageDisappearing();
_navStack.Remove(page);
PresentedPageAppearing();
InvokeNavigationRequest(args);

The fix makes OnPopToRootAsync follow the same pattern:

PresentedPageDisappearing();
_navStack = new List<Page> { null };   // equivalent of removing pages from stack
PresentedPageAppearing();
InvokeNavigationRequest(args);

This is an exact alignment with the single-level Pop lifecycle contract. ✅

Loop Guard Logic Is Correct

File: src/Controls/src/Core/Shell/ShellSection.cs

for (int i = 1; i < oldStack.Count; i++)
{
    if (i < oldStack.Count - 1)
        oldStack[i].SendDisappearing();
    RemovePage(oldStack[i]);
}

• oldStack[0] is null (the sentinel), so the loop starts at i=1.
• oldStack[oldStack.Count - 1] is the top page that was visible when pop was initiated — its SendDisappearing() was already fired by PresentedPageDisappearing() earlier.
• Intermediate pages (i=1 to i=oldStack.Count-2) correctly get SendDisappearing().
• RemovePage is called for all pages regardless. ✅

Inline Comments Are Thorough

Both changed regions include explanatory comments documenting the intent (avoiding double lifecycle events, matching single-level pop behavior). This is important for a non-obvious ordering change. ✅

Test Coverage Is Solid

• HostApp page (Issue33351.cs): Uses a custom MyTab : ShellContent that hides the tab bar on any navigation event and restores it in OnAppearing(). This precisely reproduces the reported pattern.
• Test (Issue33351.cs): Navigates two levels deep (Page1 → Page2), pops to root via GoToAsync("../.."), waits for the root page element, and does a screenshot comparison.
• Snapshots provided for all 4 platforms: Android, Mac, iOS, iOS-26, Windows. ✅

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🟡 Suggestions

1. Empty Output Table in Description

File: PR description body

The ### Output section contains a Before/After table with empty cells:

Before Issue Fix | After Issue Fix |
|----------|----------|
|||

This should either be removed or populated with actual screenshots. Empty table cells make the PR description look incomplete.

Recommendation: Remove the Output section or add the captured screenshots.

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2. Test: App.WaitForElement("Tab 1") May Be Fragile

File: src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33351.cs

App.WaitForElement("Tab 1");
App.Tap("Tab 1");

The test waits for and taps "Tab 1" by text label rather than an AutomationId. In the HostApp, "Tab 1" is the tab's Title property (not an AutomationId). This is a common pattern for tab navigation in existing Shell tests, so it likely works, but using an explicit AutomationId on the tab would be more robust.

Recommendation: Low priority — if existing Shell tests use the same convention, this is acceptable. No code change required.

---

3. Test: No Explicit Tab Bar Visibility Check Beyond Screenshot

File: src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33351.cs

The test verifies tab bar visibility only via VerifyScreenshot(). There is no programmatic assertion checking that the tab bar element is visible/accessible. This is acceptable given WaitForElement("TabBarVisibleLabel") confirms the root page is shown, and the screenshot compares the full visual state.

Recommendation: No change needed, but a future improvement could add an explicit tab bar element check if screenshot comparisons are flaky across OS versions.

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🔴 Critical Issues

None.

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[kubaflo]

Hi @BagavathiPerumal I guess something got broken here #34280 , so you opened a new pr right?

Did you change anything or just copy paste everything

[BagavathiPerumal]

Hi @BagavathiPerumal I guess something got broken here #34280 , so you opened a new pr right?

Did you change anything or just copy paste everything

Yes @kubaflo, a new PR was opened because the previous PR contained some unintended code changes that were introduced during the rebase process. To avoid confusion and keep the history clean, the PR was recreated.

The changes were not simply copy-pasted. The updates from the previous PR were retained, and the AI review comments have also been addressed. Specifically:

1. Updated the comment to explicitly clarify that RemovePage() is still called for all pages.

2. Added cleanup logic to unsubscribe from Shell.Current.Navigating when the tab disappears. This ensures the handler does not fire when the tab is no longer active. The existing -= / += pattern in OnAppearing() is retained to prevent duplicate subscriptions if the tab appears again.

3. Removed trailing whitespace characters from blank lines between App.Tap() calls in Issue33351.cs (SharedTests).

[Copilot]

Pull request overview

This PR fixes a Shell lifecycle timing issue where tab bar visibility updates (commonly triggered from OnAppearing) could be ignored when navigating back multiple pages via GoToAsync("../..") (PopToRoot), by reordering the PopToRoot lifecycle sequence to align more closely with single-page Pop behavior. It also adds a UI test and baseline snapshots to prevent regressions across platforms.

Changes:

• Reorders ShellSection.OnPopToRootAsync to fire appearing lifecycle events before invoking the platform navigation request, and avoids duplicate disappearing for the top page.
• Adds a new Appium UITest for issue #33351 plus HostApp reproduction page.
• Adds new screenshot baselines for Android/iOS/Mac/WinUI test projects.

Reviewed changes

Copilot reviewed 3 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/Controls/src/Core/Shell/ShellSection.cs	Adjusts PopToRoot lifecycle ordering and disappearing behavior.
src/Controls/tests/TestCases.HostApp/Issues/Issue33351.cs	Adds HostApp repro Shell/page structure for the issue scenario.
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33351.cs	Adds Appium UITest that navigates and verifies tab bar visibility via screenshot.
src/Controls/tests/TestCases.Android.Tests/snapshots/android/TabBarVisibilityAfterMultiLevelPopToRoot.png	New Android baseline screenshot.
src/Controls/tests/TestCases.iOS.Tests/snapshots/ios/TabBarVisibilityAfterMultiLevelPopToRoot.png	New iOS baseline screenshot.
src/Controls/tests/TestCases.Mac.Tests/snapshots/mac/TabBarVisibilityAfterMultiLevelPopToRoot.png	New Mac baseline screenshot.
src/Controls/tests/TestCases.WinUI.Tests/snapshots/windows/TabBarVisibilityAfterMultiLevelPopToRoot.png	New Windows baseline screenshot.

[sheiksyedm]

/azp run maui-pr-uitests

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