This issue has been moved from a ticket on Developer Community.

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[severity:It bothers me. A fix would be nice]
So I am currently on Windows 11 using the https://github.com/MahApps/MahApps.Metro Framework which by default makes the window squared like windows 10, so I saw a post by Microsoft here https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/apply-rounded-corners which applies rounded corners. But my question is how can I go about modifying the gray border that is drawn by the system on my window, to perhaps a different color for example? I would like the border to match my app theme.

Below is my MainWindow.cs

///

/// Interaction logic for MainWindow.xaml
///

public partial class MainWindow

{

#region Window Corner Round

public enum DWMWINDOWATTRIBUTE
{
DWMWA_WINDOW_CORNER_PREFERENCE = 33
}

// The DWM_WINDOW_CORNER_PREFERENCE enum for DwmSetWindowAttribute's third parameter, which tells the function
// what value of the enum to set.
public enum DWM_WINDOW_CORNER_PREFERENCE
{
DWMWCP_DEFAULT = 0,
DWMWCP_DONOTROUND = 1,
DWMWCP_ROUND = 2,
DWMWCP_ROUNDSMALL = 3
}

// Import dwmapi.dll and define DwmSetWindowAttribute in C# corresponding to the native function.
[DllImport("dwmapi.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern long DwmSetWindowAttribute(IntPtr hwnd,
DWMWINDOWATTRIBUTE attribute,
ref DWM_WINDOW_CORNER_PREFERENCE pvAttribute,
uint cbAttribute);
#endregion
public MainWindow()
{
InitializeComponent();

DataContext = this;

#region Window Rounding Initialization

IntPtr hWnd = new WindowInteropHelper(GetWindow(this)). EnsureHandle();
var attribute = DWMWINDOWATTRIBUTE. DWMWA_WINDOW_CORNER_PREFERENCE;
var preference = DWM_WINDOW_CORNER_PREFERENCE. DWMWCP_ROUND;
DwmSetWindowAttribute(hWnd, attribute, ref preference, sizeof(uint));

#endregion
}
}

[border-color.png] (https://aka.ms/dc/file?name=B41a02384596e4bd59e3598a2b0076874637685580918623845_border-color.png&tid=41a02384596e4bd59e3598a2b0076874637685580918623845)

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Original Comments

Feedback Bot on 9/30/2021, 00:37 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

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Original Solutions

(no solutions)