The background colour of MenuFlyoutPresenter changed to grey after upgrade

[penndai]

Describe the bug

When upgrade the Microsoft.WindowsAppSDK from version 1.3.230724000 to 1.4.230822000 (till the latest stable version Latest stable 1.7.250310001), we found the control MenuFlyout not working as before.
The issue is the background colour of the MenuFlyoutPresenter was set to "grey" colour by unknow codes rather than the value we set 'transparent'.

Steps to reproduce the bug

1. In our app, there is a MenuFlyout control, and the background colour set to transparent
   `<MenuFlyout.MenuFlyoutPresenterStyle> <Style x:Name="menuFlyoutStyle" TargetType="MenuFlyoutPresenter"> </Style>

</MenuFlyout.MenuFlyoutPresenterStyle>`
2. When click the menu, it should display the defined items with transparent background
3. Now when click the menu, the background of the MenuFlyoutPresenter set to some 'grey' colour - similar as some focused color

Expected behavior

No response

Screenshots

After upgrading to the 1.4.230822000, it displays like below

If roll back to the 1.3.230724000, it displays as below which is correct:

NuGet package version

Windows App SDK 1.7.0: 1.7.250310001

Packaging type

Unpackaged

Windows version

Windows 10 version 2004 (19041, May 2020 Update)

IDE

Visual Studio 2022

Additional context

No response

[codendone]

This is because of this feature in 1.4 (text from the 1.4 release notes):

Popup/FlyoutBase.IsConstrainedToRootBounds = false is now supported, allowing a popup/flyout to extend outside the bounds of the parent window. A SystemBackdrop property has been added to these types to support having acrylic in these unconstrained popups. Menus by default use this to have acrylic.

The default of IsConstrainedToRootBounds for a MenuFlyout is false, so it now shows in a separate window which doesn't support transparency.

You should be able to set IsConstrainedToRootBounds = true to show the flyout the same way 1.3 and earlier did (which is constrained within the window, but supports transparency and other blending effects on the content in the main window).

[penndai]

Thanks for your help, add the below property in the Menu Flyout solved my issue.