ShowMode on flyout doesn't seem to respect xaml settings

[EriWong]

Describe the bug
ShowMode is not properly being set when set from xaml. Code behind works properly.

Steps to reproduce the bug

1. Create a flyout in xaml
2. Set ShowMode to transient in xaml
3. See how focus behaves/examine the flyout properties in VS while debugging

Expected behavior
The flyout ShowMode property is set to Transient

Version Info

NuGet package version:
Microsoft.UI.Xaml 2.2.190830001

Windows 10 version	Saw the problem?
Insider Build (vb_release_ingestion.191208-1700)	Yes
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Mobile
Xbox
Surface Hub
IoT

Additional context
This was found when working on a C++/CX project

[ranjeshj]

@EriWong What is the actual behavior that you are seeing ? Do you mean to say that the control is setting the property to something else after loading ? In that case, can you attach a property change event handler on that property and get a callstack of where this is changing ? Thanks.

[msft-github-bot]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.