How do I get rid of black bar in python window?

Question

I'm working on a Object Detection project for the game Cuphead using OpenCV and Python. Now I'm trying to capture objects in real time but when the detection window displays I get this rare black bar on the top and I don't know how to get rid of it, here's what I see, on the left my object detection window and in the right the Cuphead game window.

Here's the code for the class used for this:

import numpy as np
import win32gui, win32ui, win32con

class WindowCapture:

    # define monitor's width and height
    w = 0
    h = 0
    hwnd = None

    # constructor
    def __init__(self, window_name):
        
        if window_name is None: # if we don't pass any window names capture desktop
            self.hwnd = win32gui.GetDesktopWindow()
        else:
            # Find the game window
            self.hwnd = win32gui.FindWindow(None, window_name)
            if not self.hwnd:
                raise Exception("Window not founnd: {}".format(window_name))

            # define window's widht and height. the resolution we'll work with
            window_rect = win32gui.GetWindowRect(self.hwnd)
            self.w = window_rect[2] - window_rect[0]
            self.h = window_rect[3] - window_rect[1]

    def get_screenshot(self):
        

        # get the window image data
        wDC = win32gui.GetWindowDC(self.hwnd)
        dcObj = win32ui.CreateDCFromHandle(wDC)
        cDC = dcObj.CreateCompatibleDC()
        dataBitMap = win32ui.CreateBitmap()
        dataBitMap.CreateCompatibleBitmap(dcObj, self.w, self.h)
        cDC.SelectObject(dataBitMap)
        cDC.BitBlt((0,0), (self.w, self.h), dcObj, (0,0), win32con.SRCCOPY)

        # create the screenshot image that we want to return to be processed
        signedIntsArray = dataBitMap.GetBitmapBits(True)
        img = np.fromstring(signedIntsArray, dtype='uint8')
        img.shape = (self.h, self.w, 4)

        # Free Resources
        dcObj.DeleteDC()
        cDC.DeleteDC()
        win32gui.ReleaseDC(self.hwnd, wDC)
        win32gui.DeleteObject(dataBitMap.GetHandle())

        # get rid of the alpha channel in the img
        img = img[..., :3]
        img = np.ascontiguousarray(img)

        return img

Answer 1

It seems img.shape = (self.h, self.w, 4) causes the problem. As GetWindowRect and @IInspectable said,

In Windows Vista and later, the Window Rect now includes the area occupied by the drop shadow.