[Bug] iOS 14/15 AppShell Long Press back button menu on top navigation bar hides the bottom tab bar forever

[flywhc]

AppShell iOS Long Press back button on top navigation bar hides the bottom tab bar and no workaround

Steps to Reproduce

1. create an AppShell with a bottom tabbed page
2. navigate to a page without the bottom tab bar
3. press and hold the navigation back key on the top left corner of the page
4. select a menu it popup to navigate back to the AppShell main page

Expected Behavior

AppShelll main page should display the bottom tab bar as it before

Actual Behavior

No bottom tab bar. No workaround to select a different tabbed page other than killing the app.

Basic Information

• Version with issue: 5.0.0.2125
• Last known good version: unknow
• Platform Target Frameworks:
  • iOS: 14
• NuGet Packages: Xamarin.Forms 5.0.0.2012- 5.0.0.2125
• Affected Devices: iPhone with iOS 14 or higher version

Environment

Show/Hide Visual Studio info

Version: 16.10.0.13
Hash: 1b81df5
Branch: remotes/origin/d16-10
Build date: 2021-08-12 20:43:52 UTC

Android Device Manager
Version: 16.10.0.15
Hash: 89dcc0b
Branch: remotes/origin/d16-10
Build date: 2021-08-12 20:44:10 UTC

Xamarin Designer
Version: 16.10.0.119
Hash: 36a2d986f
Branch: remotes/origin/d16-10
Build date: 2021-06-02 19:41:34 UTC

Apple Developer Tools
Xcode 12.5.1 (18212)
Build 12E507

Xamarin.Mac
Xamarin.Mac not installed. Can't find /Library/Frameworks/Xamarin.Mac.framework/Versions/Current/Version.

Xamarin.iOS
Version: 14.20.0.24 (Visual Studio Enterprise)
Hash: c4b89cddb
Branch: d16-10
Build date: 2021-06-15 22:03:01-0400

Build Information
Release ID: 810080000
Git revision: 0bc91c25997e4c374dc6eb96809c7bf52f6a7c33
Build date: 2021-08-18 14:50:30-04
Build branch: release-8.10

Operating System
Mac OS X 10.16.0
Darwin 20.6.0 Darwin Kernel Version 20.6.0
    Wed Jun 23 00:26:31 PDT 2021
    root:xnu-7195.141.2~5/RELEASE_X86_64 x86_64

Screenshots

2.

3.

Reproduction Link

https://github.com/flywhc/XamarinLongPressIssue

Workaround

No workaround. The user has to kill and restart the app.
Tried changing Shell.TabBarIsVisible in the different events but no impacts.

[jsuarezruiz]

I think is related with #14505

[flywhc]

I think is related with #14505

I don't think they are. This issue is always here since iOS 14. It is not about the background color. The bottom tab bar is truly disappeared. User could tap on tabbar area to select different pages if it is a color problem, but this one caused user cannot select different pages at all. User has to kill the app process and restart to see other pages.