TitleBar gives an NULLREF exception

Describe the bug

Getting a nullreff in the class TitleBar.cs

To Reproduce

<ui:FluentWindow x:Class="FancyAI.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:FancyAI"
xmlns:tray="http://schemas.lepo.co/wpfui/2022/xaml/tray"
xmlns:ui="http://schemas.lepo.co/wpfui/2022/xaml"
WindowCornerPreference="Round"
ExtendsContentIntoTitleBar="True"
WindowBackdropType="Mica"
Background="#55AABBCC"
mc:Ignorable="d"
Title="Fancy AI"
Height="450"
Width="800">

<ui:TitleBar x:Name="TitleBar"
VerticalAlignment="Top"
Height="32"
Title="{Binding ViewModel.ApplicationTitle}"
Grid.Row="0" />

</ui:FluentWindow>

Expected behavior

Show the titlebar...

Screenshots

No response

OS version

Windows 11

.NET version

.net framework 4.8

WPF-UI NuGet version

3.0

Additional context

No response

Start by inspecting TitleBar.cs and reproducing the provided FluentWindow/XAML example with WPF-UI 3.0 on Windows 11 and .NET Framework 4.8. Trace the null reference and confirm that the TitleBar renders without the exception; the issue does not identify a test or a more specific expected change.