SDL Mouse position Cropped after resizing

I get strange behavior with mouse position in SDL. If I resized the window larger, then the x, y positions from the mouse events will be limited to the original Width and Height window.

If there is any function call that I’m missing, to tell the SDL that the area of ​​the cape has increased in size.

Relevant parts of the application:

void Resize(int width, int height)
{
    WindowWidth = width;
    WindowHeight = height;
    /* update OpenGL */
}

void Init()
{
    glClearColor(0.f, 0.f, 0.f, 1.f);
    Resize(WindowWidth, WindowHeight);
}

void MouseClick(int button, int state, int x, int y)
{
    unsigned int MouseButton = unsigned(Mouse.z);
    unsigned int b = (1 << (button-1));
    if (state)
        MouseButton = MouseButton | b;
    else
        MouseButton = MouseButton & (~b);
    Mouse.z = MouseButton;
    Mouse.x = x;
    Mouse.y = y;
}

void MouseMove(int x, int y)
{
    MouseRel.x = x - Mouse.x;
    MouseRel.y = y - Mouse.y;
    Mouse.x = x;
    Mouse.y = y;
}

int main(int agrc, char *argv[])
{
    bool quit = false;
    SDL_Event event;

    if ( SDL_Init(SDL_INIT_VIDEO) < 0)
        return 1;

    if (SDL_SetVideoMode(WindowWidth, WindowHeight, 0, SDL_OPENGL | SDL_RESIZABLE) == NULL)
        return 2;

    Init();

    while (!quit)
    {
        DrawScene();
        while ( SDL_PollEvent(&event) )
        {
            if ( event.type == SDL_VIDEORESIZE)
            {
                Resize(event.resize.w, event.resize.h);
            }
            else if ( event.type == SDL_MOUSEBUTTONDOWN || event.type == SDL_MOUSEBUTTONUP )
            {
                MouseClick(event.button.button, event.button.state, event.button.x, WindowHeight - event.button.y);
                printf("event.button (%i, %i)\n", event.button.x, event.button.y);
                MouseHandler();
            }
            else if ( event.type == SDL_MOUSEMOTION )
            {
                MouseMove(event.motion.x, WindowHeight - event.motion.y);
                printf("event.motion (%i, %i)\n", event.motion.x, event.motion.y);
                MouseHandler();
            }
            else if (event.type == SDL_QUIT)
                quit |= true;
        }
        quit |= KeyboardHandler();
        SDL_Delay(10);
    }
    SDL_Quit();
    return 0;
}