Setting the titlebar control back button visible through C# for the first time allows it to be dragged and removes animation

Describe the bug

When you set the TitleBar back button visible through C# (not XAML) the first time, it allows you to drag the window by the back button and removes the back button animation.

Steps to reproduce the bug

1. Create a titlebar control in XAML with the back button IsBackButtonVisible false
2. In the .xaml.cs file, set the IsBackButtonVisible to true
3. Observe that you can drag the window by the back button and the animation is removed

Minimum reproduction:
https://github.com/RyanLua/TitlebarTest/tree/main/TitlebarTest

Expected behavior

Setting the back button in the titlebar control should retain the same behaviors as when setting it through XAML.

Screenshots

https://github.com/user-attachments/assets/1c566f04-33cd-499b-94a3-e0f919b04d8f

NuGet package version

WinUI 3 - Windows App SDK 1.7 Preview 1: 1.7.250208002-preview1

Windows version

Windows 11 (24H2): Build 26100

Additional context

If you set the back button invisible and set it visible it again, it works like normal as expected. The first time you make the back button visible is when it is in this bugged state.

Run the linked TitlebarTest minimum reproduction, starting with the titlebar XAML and its .xaml.cs code that toggles IsBackButtonVisible. Verify that first-time runtime visibility preserves the back button's drag behavior and animation, matching XAML initialization; done means the reported behavior no longer occurs.