Making a custom titlebar

[BleastT]

Hey so on windows i added this code:

#define GLFW_EXPOSE_NATIVE_WIN32
#include <GLFW/glfw3.h>
#include <GLFW/glfw3native.h>

#include <Windows.h>
#include <dwmapi.h>

    void disableTitlebar(GLFWwindow* window)
    {
        HWND hWnd = glfwGetWin32Window(window);

        // Remove the title bar
        LONG_PTR lStyle = GetWindowLongPtr(hWnd, GWL_STYLE);
        lStyle &= ~WS_CAPTION;
        SetWindowLongPtr(hWnd, GWL_STYLE, lStyle);

        // Set the window shape and rounded corners
        DWMNCRENDERINGPOLICY policy = DWMNCRP_ENABLED;
        DwmSetWindowAttribute(hWnd, DWMWA_NCRENDERING_POLICY, &policy, sizeof(policy));

        // Extend the frame into the client area
        MARGINS margins = { 0 };
        DwmExtendFrameIntoClientArea(hWnd, &margins);

        // Adjust the window size to remove the thin frame at the top
        RECT windowRect;
        GetWindowRect(hWnd, &windowRect);
        SetWindowPos(hWnd, NULL, 0, 0, windowRect.right - windowRect.left, windowRect.bottom - windowRect.top, SWP_FRAMECHANGED | SWP_NOMOVE);
    }

With this, the titlebar disappear and im able to keep resizing and rounded corners. Snapping the window also works on windows 11-10.

Unfortunately there is a small issue. In the place where there was the title bar, there is a very thin white frame which does not have any purpose. It’s just there and it’s really annoying.
I cant find a way to remove it