Window capture mode cannot retrieve all screens of this window handle

The window capture mode cannot capture the entire screen of this window handle and can only capture a portion of the screen.

The debug log is as follows：
Filter name: Sample Grabber
Filter CLSID: {c1f400a0-3f08-11d3-9f0b-006008039e37}
Pin 0 - Input - Input
Connected to: Color Space Converter, XForm Out
Connection media type: 640x384 RGB, 24 bit, Frame rate: 30.00
Pin 1 - Output - Output
Connected to: Video Sample Grabber, Input
Connection media type: 640x384 RGB, 24 bit, Frame rate: 30.00

The program is as follows：
ScreenCaptureSourceSettings sourceSettings = new ScreenCaptureSourceSettings
{
FullScreen = false,
WindowHandle = windowHandle,
FrameRate = VideoFrameRate.FPS_30,
GrabMouseCursor = true,
Mode = ScreenCaptureMode.Window
};


Problem: The window size is 841x529, and the logging program can only capture a range of 640x384