`ExtendContentToNonClientArea` not work as expected

[GF-Huang]

Describe the bug

When set hc:WindowAttach.ExtendContentToNonClientArea="True", the non-client area cover the client content.

Steps to reproduce the bug

Code for reproduce:

<hc:Window x:Class="HandyControlProject1.Views.RootView"
           ...
           hc:WindowAttach.ExtendContentToNonClientArea="True">
  <Grid Background="Green">
    <TextBlock Text="123456" Foreground="Black" FontSize="50" />
  </Grid>
</hc:Window>

Expected behavior

No response

Screenshots

No response

NuGet package version

HandyControls (Custom version) 3.5.0

IDE

Visual Studio 2022

Framework type

.Net 8.0

Windows version

Windows 11 22H2 22621.2715

Additional context

No response