enlarging a window produces clipping

Hello,
I am studying X, and confused some problems. If I enlarge the window, the drawing is clipped to the size of the window before enlarging. there is a test program

Code:

---

#include <X11/Xlib.h>
#include <iostream>

int main()
{
        // Open the display
        Display *dpy = XOpenDisplay(NIL);
        Window desktop = DefaultRootWindow(dpy);

        // Get some colors
        int whiteColor = WhitePixel(dpy, DefaultScreen(dpy));


        // Create the window
        hwnd_t wnd = XCreateSimpleWindow(dpy, desktop,

                                                                                10, 10, 300, 200, 0,0,

                                                                                whiteColor);



        XSelectInput(dpy, wnd, StructureNotifyMask | ButtonPressMask | ExposureMask| ResizeRedirectMask); //POINT A

      XMapWindow(dpy, wnd);

      XFlush(dpy);

        XEvent event;
        while(true)
        {
                XNextEvent(dpy, &event);
                switch(event.type)
                {
                case ButtonPress:
                        std::cout<<"button clicked"<<std::endl;
                }
        }
}

---

the code shows when a mouse clicked on the window, it prints "button clicked" in terminal. but after enlarging the window, the event just effects the original rectangle before enlarging, if a mouse clicked on the new rectangle, "button clicked" is not printed in terminal.

at the comment POINT A, if i modify the line to
XSelectInput(dpy, wnd, StructureNotifyMask | ButtonPressMask | ExposureMask);
the window is allright. please show me a solution on the problem.

thanks in advance

> switch(event.type)
You need to respond to resize events as well (I guess).
Been over a decade since I last rummaged in low-level X11

Sorry, I don't know what your meaning is...
essentially, i think iit is ResizeRedirectMask

Code:

---

                case default:
                        std::cout<<"An ignored event"<<std::endl;

---

Get many of these?

>>Get many of these?

yes. if i resize the window