Overflow during the conversion from a Message.LParam to the Point for the NonClientHitTest

[PaceyIV]

In the RibbonFormHelper::WndProc there is this peace of code

else if (m.Msg == WinApi.WM_NCHITTEST && (int)m.Result == 0) //0x84
{
        m.Result = new IntPtr(Convert.ToInt32(NonClientHitTest(WinApi.GetPoint(m.LParam))));
        handled = true;
}

The cast to int is wrong. I have received a message with LParam = 4294508536 that throw an Overflow exception.

I suggest this function to convert a LParam to the corresponding x,y coordinate

/// <summary>
/// Retrieve the signed x,y-coordinate from the specified LPARAM value`
/// </summary>
/// <param name="lParam"></param>
/// <returns></returns>
public static Point GetPoint(IntPtr lParam)
{
        int value = unchecked((int)(long)lParam);
        int x = (short)(value & 0xffff);
        int y = (short)((value >> 16) & 0xffff);
        return new Point(x, y);
}

See also this API https://docs.microsoft.com/en-us/windows/win32/api/windowsx/nf-windowsx-get_x_lparam