[c++] WinAPI WM_COMMAND: kliknięcie na kontrolkę EDIT zamyka całe okno.

void CreateEdit( const HWND & hWnd, const HINSTANCE & hInst, HWND & g_hEdit ) {
    g_hEdit = CreateWindowEx( WS_EX_CLIENTEDGE,( LPCWSTR ) _T( "EDIT" ), NULL,
    WS_CHILD | WS_VISIBLE | WS_BORDER | WS_VSCROLL | ES_MULTILINE | ES_AUTOVSCROLL,
    10, 10, 500, 300, hWnd, NULL, hInst, NULL );
    if( !g_hEdit )
         SendMessage( hWnd, WM_CLOSE, NULL, NULL );
   
    SetWindowText( g_hEdit, _T( "Wpisz tu coś..." ) );
}

void CreateButton( const HWND & hWnd, const HINSTANCE & hInst, HWND & g_hButW, HWND & g_hButC ) {
    g_hButW = CreateWindowEx( WS_EX_CLIENTEDGE,( LPCWSTR ) _T( "BUTTON" ), _T( "Zapisz tekst" ),
    WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 350, 150, 30,
    hWnd,( HMENU ) ID_BUTTON_WRITE, hInst, NULL );
    if( !g_hButW ) SendMessage( hWnd, WM_CLOSE, NULL, NULL );
   
    g_hButC = CreateWindowEx( WS_EX_CLIENTEDGE,( LPCWSTR ) _T( "BUTTON" ), _T( "Wyjdź" ),
    WS_CHILD | WS_VISIBLE | WS_BORDER, 200, 350, 150, 30,
    hWnd,( HMENU ) ID_BUTTON_CLOSE, hInst, NULL );
    if( !g_hButC ) SendMessage( hWnd, WM_CLOSE, NULL, NULL );
   
}

LRESULT CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam ) {
    switch( msg ) {
    case WM_CREATE:
        CreateEdit( hWnd, hInst, g_hEdit );
        CreateButton( hWnd, hInst, g_hBut_write, g_hBut_close );
        break;
    case WM_COMMAND:
        switch( wParam ) {
        case ID_BUTTON_WRITE:
            WriteFile( hFout, g_hEdit, hWnd );
            break;
        case ID_BUTTON_CLOSE:
            DestroyWindow( hWnd );
            break;
        }
    case WM_CLOSE:
        DestroyWindow( hWnd );
        break;
    case WM_DESTROY:
        PostQuitMessage( 0 );
        break;
        default:
        return DefWindowProc( hWnd, msg, wParam, lParam );
    }
    return 0;
}

case WM_COMMAND:
switch( wParam ) {
case ID_BUTTON_WRITE:
    WriteFile( hFout, g_hEdit, hWnd );
    break;
case ID_BUTTON_CLOSE:
    DestroyWindow( hWnd );
    break;
}
break;

if( !g_hEdit )
     SendMessage( hWnd, WM_CLOSE, NULL, NULL );