Repaint child window's controls using win32 API - c++

Question

I have a main window which has a child window which in turn have a child window and a button. When i restore the window from taskbar the button and third child window refuse to display. I tried using RedrawWindow() on the child first, and then the grand child and the button but didnt work. So far it looks like there is no connection between the child window and its child cos the parent is responsible for repainting its child, but the child has no duty. How do i repaint child window's controls / child window (child of a child), during parent (main window) repaint. That is after restore of parent using Win32 API.
I created a control class as the entry point of the app and to oversee all other classes(Screen class- for GUI, Database class...), the Screen class have all the child creation codes in it. This how:
//MainControl Class
#include <tchar.h>
#include "Screen.h"
#include <stdlib.h>
#include "FreeImage.h"
#pragma comment(lib, "user32")
#pragma comment(lib,"gdi32.lib")
#pragma comment(lib,"FreeImage.lib")
const char g_szClassName[] = "myWindowClass";
Screen display;
HWND welcomScreenHndl, menuScreenHndl, butt;
// Function prototypes
LRESULT CALLBACK WndProc(HWND hwnd, UINT messages, WPARAM wParam, LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine,
int nCmdShow){
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
// Registering the Window Class.
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH) (COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc)){
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Creating the Window.
hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, g_szClassName,
"Prison Management System",
WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX | WS_CLIPCHILDREN,
100, 30, 750, 700, NULL, NULL, hInstance, NULL);
if(hwnd == NULL){
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Creating Other Windows with Scree class object.
welcomScreenHndl = display.welcomeScreen(hwnd, hInstance);//Child to Main Window
menuScreenHndl = display.menuScreen(welcomScreenHndl, hInstance);//grand child
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// The message loop.
while(GetMessage(&Msg, NULL, 0, 0) > 0){
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
Here is the Screen class: // Screen Class
#include <tchar.h>
#include <windows.h>
class Screen{
char winClassName[20];
public:
HWND welcomeScreen(HWND parent, HINSTANCE hInstance);
HWND menuScreen(HWND parent, HINSTANCE hInstance);
};
HWND Screen::welcomeScreen(HWND parent, HINSTANCE hInstance){
GetClassName(parent, winClassName, 20);
HWND hwndpan = CreateWindowEx( WS_EX_CLIENTEDGE,
winClassName,
"",
WS_CHILD | WS_VISIBLE | CS_HREDRAW | CS_VREDRAW,
0, 20, 745, 695,
parent, NULL, hInstance/*GetModuleHandle(NULL)*/, NULL);
return hwndpan;
}
HWND Screen::menuScreen(HWND parent, HINSTANCE hInstance){
HWND hwndpan = CreateWindowEx( WS_EX_CLIENTEDGE,
winClassName,
"",
WS_CHILD | WS_VISIBLE | CS_HREDRAW | CS_VREDRAW,
0, 100, 745, 695,
parent, NULL, hInstance/*GetModuleHandle(NULL)*/, NULL);
return hwndpan;
}