C++ Win32, How to add a dropdown menu to a Win32 DialogBox

Hi, 

This is my first time posting quesiton to stackoverflow. 

I am trying to add combobox (in menu.cpp) to a Win32 Dialogbox (in fingerspell.cpp). I am not very fluent in Win32 
programming and most of the msdn example snippets draw a combobox inside a window. Even though Dialogbox is technically
a window but I haven't had much progress in modifing any window example code to handle a DialogBox. I would really appreciate a working example. 

A rough sketch of the code is as follows. fingerspell.cpp creates implements the WinMain function and then calls up
other custom classes to draw inside this DialogBox. No other window controls, like buttons, text area etc, are used. 

code for fingerspell.cpp is 

```
#include "fingerspell.h"
extern "C" __declspec(dllexport)bool isGloveDriverInstalled();
extern "C" __declspec(dllimport)bool initialize();

#define RUN( x ) if ( SUCCEEDED( result ) ) { result = x; }

BOOL g_fullscreen = FALSE;
bool portReady;

INT_PTR CALLBACK OptionDialogProc( HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam) 
{
    switch (uMsg) {
        case WM_INITDIALOG:
            if (wParam == IDOK)
                return TRUE ;
            else
                return FALSE ;
            break;

        case WM_COMMAND:
            if (HIWORD(wParam) == BN_CLICKED) {
                if (LOWORD(wParam) == IDOK) {
                    g_fullscreen = TRUE;
                    EndDialog (hwndDlg, 1) ;
                }
                else if (LOWORD(wParam) == ID_WINDOW_OPT) {
                    g_fullscreen = FALSE;
                    EndDialog (hwndDlg, 1) ;
                }
                else {
                    EndDialog (hwndDlg, 0) ;
                }

                return TRUE ;
            }

        default:
            return FALSE;
            break ;
    }
}

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow )
{
    INT_PTR DispOption = DialogBox (hInstance, MAKEINTRESOURCE(IDD_DISPLAY_OPTIONS), NULL, OptionDialogProc) ;
    if (DispOption == 0)
        return 0 ;

    //srand( GetTickCount( ) );

    HRESULT result = S_OK;

    if (!isGloveDriverInstalled())
    {
        portReady = FALSE;
        MessageBox(NULL, "The Glove Driver is not istalled ", "Error", MB_OK );
    }
    else 
    {
        if (!initialize())
        {
            portReady = FALSE;
            MessageBox(NULL, "Error Opening Com Port", "Error", MB_OK );
        }
        else
        {
            portReady = TRUE;
        }
    }

    RUN( Words ::Create     ( "default.txt" ) );
    RUN( Window::Create     ( ) );
    RUN( Render::Create     ( ) );
    RUN( Art   ::Create     ( ) );
    RUN( Menu  ::Create     ( ) );
    RUN( Window::MessageLoop( ) );
    RUN( Menu  ::Destroy    ( ) );
    RUN( Art   ::Destroy    ( ) );
    RUN( Render::Destroy    ( ) );
    RUN( Window::Destroy    ( ) );
    RUN( Words ::Destroy    ( ) );

    if ( FAILED( result ) )
    {
        MessageBox( GetDesktopWindow( ), "Warning - Fail Code Detected", "Fingerspell 2002", MB_ICONWARNING | MB_OK );
    }

    return result;
}

```

code for menu.cpp. file where im trying to add combobox. 

```
#include "fingerspell.h"

#include <windows.h>  //include all the basics
#include <tchar.h>    //string and other mapping macros
#include <string>

HRESULT Menu::Create(  )
{
    // set menu as the background
    Render::SetBackground( ART_MENU );
    // clear overlay
    Render::Reset( );
    Window::SetProc( Proc );
    return S_OK;
}

HRESULT Menu::Destroy( void )
{
    return S_OK;
}

LRESULT CALLBACK Menu::Proc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
{
    DWORD i ;

    const static RECT button_rect[ 8 ] =
    {
        { 52,  139, 52 + 101,  139 + 50 }, //1. about
        { 55,  212, 55 + 85,  212 + 50 }, // 2. learn
        { 67,  280, 67 + 63,  280 + 50 }, // 3. exit
        { 397, 137, 397+ 233, 137 + 50 }, // 4. Add Delete List. 
        { 421, 187, 421+ 183, 187 + 50 }, // 5. add word
        { 413, 247, 413+ 201, 247 + 50 }, // 6. delete word
        { 450, 300, 450+ 124, 300 + 50 }, // 7. practice
        { 473, 349, 473 + 82,  349 + 50 }, // 8. test

    };

    // custom message processing

    switch ( uMsg )
    {
        case WM_CREATE:
            return OnCreate(hwnd,reinterpret_cast<CREATESTRUCT*>(lParam));

        case WM_MOUSEMOVE: // move is moved, see where  is it pointing to. 
        {
            int xPos = GET_X_LPARAM( lParam );
            int yPos = GET_Y_LPARAM( lParam );

            for ( i = 0; i < 8; i++ )
            {
                if ( xPos >= button_rect[ i ].left && yPos >= button_rect[ i ].top )
                {
                    if ( xPos < button_rect[ i ].right && yPos < button_rect[ i ].bottom )
                    {
                        // set selection

                        Render::SetOverlay( 0, (ART) ( ART_MENU_LEARN + i ), button_rect[ i ].left, button_rect[ i ].top );

                        break;
                    }
                }
            }

            if ( i == 8 )
            {
                 //remove selection

                Render::SetOverlay( 0, ART_NULL, 0, 0 );
            }

            return 0;
        }

        case WM_LBUTTONDOWN:
        {
            switch ( Render::GetOverlay( 0 ) )
            {
                case ART_MENU_EXIT: // done. 
                {
                    Menu::Destroy( );

                    Learn::Create( );

                    break;
                }

                case ART_MENU_LEARN: // done 
                {
                    Menu::Destroy( );

                    About::Create( );

                    break;
                }

                case ART_MENU_ABOUT: // done 
                {
                    Menu::Destroy( );

                    Test::Create( );

                    break;
                }

                case ART_MENU_TEST: // done. 
                {
                    Menu::Destroy( );

                    Practice::Create( );

                    break;
                }

                case ART_MENU_DELETEWORD: // done 
                {
                    Menu::Destroy( );

                    AddWord::Create( );

                    break;
                }

                case ART_MENU_ADDDELETELIST:
                {
                    //Menu::Destroy () ;

                    PostQuitMessage( 0 );

                    break;
                }

                case ART_MENU_ADD:
                {
                    Menu::Destroy( );

                    // About is place holder. should be AddDELETELIST
                    About::Create( );

                    break;
                }

                case ART_MENU_PRACTICE: // done. 
                {
                    Menu::Destroy( );

                    // About is place holder. shd be DELETEWORD. 
                    About::Create( );

                    break;
                }

            }

            return 0;

        }

    }

    // default message processing

    return DefWindowProc( hwnd, uMsg, wParam, lParam );
}

```

Thanks.