Вопрос по Winapi

#include <windows.h>
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
HINSTANCE g_hinst;
 
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
  HWND hwnd;
  MSG  msg ;
  WNDCLASS wc = {0};
  wc.lpszClassName = TEXT("Application");
  wc.hInstance     = hInstance ;
  wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
  wc.lpfnWndProc   = WndProc ;
  wc.hCursor       = LoadCursor(0,IDC_ARROW);
 
  g_hinst = hInstance;
 
  RegisterClass(&wc);
  hwnd = CreateWindow(wc.lpszClassName, TEXT("Combo Box"),WS_OVERLAPPEDWINDOW | WS_VISIBLE,100, 100, 270, 170, 0, 0, hInstance, 0);
 
 
  while( GetMessage(&msg, NULL, 0, 0)) {
    DispatchMessage(&msg);
  }
  return (int) msg.wParam;
}
 
LRESULT CALLBACK WndProc( HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam )
{
 
  static HWND hwndCombo, hwndStatic;
  const TCHAR *items[] = { TEXT("programina_1"), TEXT("programina_2"),TEXT("programina_3"), TEXT("programina_4") };
  int i;
  LRESULT sel = 0;
 
  switch(msg)
  {
      case WM_CREATE:
            hwndCombo = CreateWindow(TEXT("combobox"), NULL, WS_CHILD | WS_VISIBLE | CBS_DROPDOWN,10, 10, 120, 110, hwnd, NULL, g_hinst, NULL);
            hwndStatic = CreateWindow(TEXT("static"), TEXT(""),WS_CHILD | WS_VISIBLE,150, 80, 90, 25, hwnd, NULL, g_hinst, NULL);
 
            for ( i = 0; i < 4; i++ ) {
                SendMessage(hwndCombo, CB_ADDSTRING, 0, (LPARAM) items[i]);
            }
            break;
 
      case WM_COMMAND:
           if ( HIWORD(wParam) == CBN_SELCHANGE) {
                sel = SendMessage(hwndCombo, CB_GETCURSEL, 0, 0);
                SetWindowText(hwndStatic, items[sel]);
                SetFocus(hwnd);
           }
           break;
 
      case WM_DESTROY:
          PostQuitMessage(0);
          break;
  }
  return DefWindowProc(hwnd, msg, wParam, lParam);
}