TrackBar не реагирует или почему не работает WM_ITINDIALOG?

#include <Windows.h>
#include <wchar.h>
#include <commctrl.h>
 
PAINTSTRUCT ps;
HDC hdc;
 
HINSTANCE hInst;
HWND hwndTrackbar;
HWND WINAPI CreateTrackbar(
    HWND,
    UINT,
    UINT,
    UINT,
    UINT
);
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
TCHAR WinName[] = L"MainFrame";
int WINAPI WinMain(
    HINSTANCE This,
    HINSTANCE Prev,
    LPSTR cmd,
    int mode
)
{
    hInst = This;
    HWND hWnd;
    MSG msg;
    WNDCLASS wc;
    wc.hInstance = This;
    wc.lpszClassName = WinName; 
    wc.lpfnWndProc = WndProc; 
    wc.style = CS_HREDRAW | CS_VREDRAW; 
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION); 
    wc.hCursor = LoadCursor(NULL, IDC_ARROW); 
    wc.lpszMenuName = NULL; 
    wc.cbClsExtra = NULL; 
    wc.cbWndExtra = NULL;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    if (!RegisterClass(&wc)) return NULL;
    int WindowWidth = 400;
    int WindowHeight = 250;
    int ScreenWidth = GetSystemMetrics(SM_CXSCREEN) - WindowWidth;
    int ScreenHeight = GetSystemMetrics(SM_CYSCREEN) - WindowHeight;
    hWnd = CreateWindow(
        WinName, 
        L"Title", 
        WS_VISIBLE | WS_SYSMENU | WS_MINIMIZEBOX, 
        ScreenWidth / 2, //x позиция
        ScreenHeight / 2,  //y позиция
        WindowWidth, //ширина
        WindowHeight, //высота
        HWND_DESKTOP, 
        NULL, 
        This, 
        NULL 
    );
    ShowWindow(hWnd, mode);
    while (GetMessage(&msg, NULL, NULL, NULL))
    {
        TranslateMessage(&msg); 
        DispatchMessage(&msg); 
    }
    return NULL;
}
 
LRESULT CALLBACK WndProc(
    HWND hWnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam
)
{
    switch (message)
    {
    case WM_INITDIALOG:
        CreateTrackbar(hWnd, 0, 100, 10, 50);
        break;
    case WM_PAINT:
        break;
    case WM_DESTROY:
        PostQuitMessage(NULL);
        break;
    default: return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return NULL;
}
 
HWND WINAPI CreateTrackbar(
    HWND hwnd,
    UINT iMax,
    UINT iMin,
    UINT iSelMax,
    UINT iSelMin
)
{
    hwndTrackbar = CreateWindowEx(
        NULL,
        TRACKBAR_CLASS,
        L"TrackBar control",
        WS_CHILD | WS_VISIBLE | TBS_AUTOTICKS | TBS_ENABLESELRANGE,
        10,
        10,
        200,
        30,
        hwnd,
        NULL,
        hInst,
        NULL
    );
    SendMessage(hwndTrackbar, TBM_SETRANGE, (WPARAM)TRUE, (LPARAM)MAKELONG(iMin, iMax));
    SendMessage(hwndTrackbar, TBM_SETPAGESIZE, (WPARAM)0, (LPARAM)10);
    SendMessage(hwndTrackbar, TBM_SETSEL, (WPARAM)FALSE, (LPARAM)MAKELONG(iSelMin, iSelMax));
    SetFocus(hwndTrackbar);
 
    return hwndTrackbar;
}