My Full Code

#define _WIN32_WINNT 0x0600
#define _WIN32_IE 0x0900
#include <windows.h>
#include <commctrl.h>
#include <Tchar.h>

#define IDC_BUTTON_1 101
#define IDC_EDIT_1 201
#define IDC_EDIT_2 202
#define IDC_STATIC_1 301
#define IDC_STATIC_2 302
#define IDC_COMBO_BOX_1 401

const char g_ClassName[] = "WindowClass1";
HIMAGELIST g_himl;

LRESULT CALLBACK MainWindowProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    switch(Message) {
        case WM_CTLCOLORSTATIC: {
            DWORD CtrlID = GetDlgCtrlID((HWND)lParam);

            if (CtrlID = IDC_STATIC_1) {
                HDC hdcStatic = (HDC) wParam;
                SetBkMode(hdcStatic, TRANSPARENT);
                SetBkColor(hdcStatic, RGB(230,230,230));
            }
        }
        break;
        case WM_COMMAND: {
            switch(LOWORD(wParam)) {
                case IDC_BUTTON_1: {

                    int TextLen1 = GetWindowTextLength(GetDlgItem(hwnd, IDC_EDIT_1));
                    int TextLen2 = GetWindowTextLength(GetDlgItem(hwnd, IDC_EDIT_2));

                    if(TextLen1 > 0) {
                        char* buf;

                        buf = (char*)GlobalAlloc(GPTR, TextLen1 + 1);
                        GetDlgItemText(hwnd, IDC_EDIT_1, buf, TextLen1 + 1);

                        if(TextLen2 > 0) {
                            char* buf2;

                            buf2 = (char*)GlobalAlloc(GPTR, TextLen2 + 1);
                            GetDlgItemText(hwnd, IDC_EDIT_2, buf2, TextLen2 + 1);

                            MessageBox(hwnd, buf, buf2, MB_OK | MB_ICONINFORMATION);

                            GlobalFree((HANDLE)buf2);

                        } else {
                             MessageBox(hwnd, "Not enough information!", "ERROR", MB_OK | MB_ICONWARNING);
                        }


                        GlobalFree((HANDLE)buf);
                    } else {
                        MessageBox(hwnd, "Not enough information!", "ERROR", MB_OK | MB_ICONWARNING);
                    }

                }
            }
        }
        break;
        case WM_CREATE: {
            HWND Combo1 = CreateWindowEx(
            NULL, WC_COMBOBOXEX, NULL,
            WS_BORDER | WS_VISIBLE | WS_CHILD | CBS_DROPDOWN,
            0, 0, 0, 100,
            hwnd, (HMENU)IDC_COMBO_BOX_1,
            GetModuleHandle(NULL), NULL);

            //Combo Box Items START
            COMBOBOXEXITEM cbei;
            int iCnt;

            typedef struct {
                int iImage;
                int iSelectedImage;
                int iIndent;
                LPTSTR pszText;
            } ITEMINFO, *PITEMINFO;

            ITEMINFO IInf[] = {
                {0, 3, 0, _T("first")},
                {1, 4, 1, _T("second")},
                {2, 5, 2, _T("third")},
                {0, 3, 0, _T("fourth")},
                {1, 4, 1, _T("fifth")},
                {2, 5, 2, _T("sixth")},
                {0, 3, 0, _T("seventh")},
                {1, 4, 1, _T("eighth")},
                {2, 5, 2, _T("ninth")},
                {0, 3, 0, _T("tenth")},
                {1, 4, 1, _T("eleventh")},
                {2, 5, 2, _T("twelfth")},
                {0, 3, 0, _T("thirteenth")},
                {1, 4, 1, _T("fourteenth")},
                {2, 5, 2, _T("fifteenth")},
            };

            cbei.mask = CBEIF_TEXT | CBEIF_INDENT | CBEIF_IMAGE | CBEIF_SELECTEDIMAGE;

            for(iCnt = 0; iCnt < 15; iCnt++) {
                cbei.iItem = iCnt;
                cbei.pszText = IInf[iCnt].pszText;
                cbei.cchTextMax = sizeof(IInf[iCnt].pszText);
                cbei.iImage = IInf[iCnt].iImage;
                cbei.iSelectedImage = IInf[iCnt].iSelectedImage;
                cbei.iIndent = IInf[iCnt].iIndent;

                if(SendMessage(Combo1, CBEM_INSERTITEM, 0, (LPARAM)&cbei) == -1) {
                    return FALSE;
                }
            }

            SendMessage(Combo1, CBEM_SETIMAGELIST, 0, (LPARAM)g_himl);
            SetWindowPos(Combo1, NULL, 20, 20, 250, 120, SWP_NOACTIVATE);


            //Combo Box Items END

            HWND Button1 = CreateWindowEx(
                NULL,
                "BUTTON",
                "Create Message Box",
                WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON | BS_TEXT,
                10, 275, 360, 25,
                hwnd,
                (HMENU)IDC_BUTTON_1,
                GetModuleHandle(NULL),
                NULL);

            if (Button1 == NULL) {
                MessageBox(NULL, "Failed to create button1!", "ERROR!", MB_OK | MB_ICONWARNING);
                return -1;
            }

            HWND Edit1 = CreateWindowEx(
                WS_EX_CLIENTEDGE,
                "EDIT",
                "",
                WS_VISIBLE | WS_BORDER | WS_CHILD | ES_MULTILINE,
                100, 110, 270, 150,
                hwnd,
                (HMENU)IDC_EDIT_1,
                GetModuleHandle(NULL),
                NULL);

            if (Edit1 == NULL) {
                MessageBox(NULL, "Failed to create edit1!", "ERROR!", MB_OK | MB_ICONWARNING);
                return -1;
            }

            HWND Edit2 = CreateWindowEx(
                WS_EX_CLIENTEDGE,
                "EDIT",
                "",
                WS_VISIBLE | WS_BORDER | WS_CHILD,
                100, 70, 270, 30,
                hwnd,
                (HMENU)IDC_EDIT_2,
                GetModuleHandle(NULL),
                NULL);

            if (Edit2 == NULL) {
                MessageBox(NULL, "Failed to create edit2!", "ERROR!", MB_OK | MB_ICONWARNING);
                return -1;
            }

            HWND Static1 = CreateWindowEx(
                NULL,
                "STATIC",
                "Title:",
                WS_VISIBLE | WS_CHILD | SS_CENTER,
                0, 75, 100, 20,
                hwnd,
                (HMENU)IDC_STATIC_1,
                GetModuleHandle(NULL),
                NULL);

            if (Static1 == NULL) {
                MessageBox(NULL, "Failed to create static1!", "ERROR!", MB_OK | MB_ICONWARNING);
                return -1;
            }

            HWND Static2 = CreateWindowEx(
                NULL,
                "STATIC",
                "Message:",
                WS_VISIBLE | WS_CHILD | SS_CENTER,
                0, 115, 100, 20,
                hwnd,
                (HMENU)IDC_STATIC_2,
                GetModuleHandle(NULL),
                NULL);

            if (Static2 == NULL) {
                MessageBox(NULL, "Failed to create static2!", "ERROR!", MB_OK | MB_ICONWARNING);
                return -1;
            }


        }
        break;
        case WM_CLOSE:
            DestroyWindow(hwnd);
            ImageList_Destroy(g_himl);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default:
            DefWindowProc(hwnd, Message, wParam, lParam);
    }
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    INITCOMMONCONTROLSEX icex;
    icex.dwSize = sizeof(INITCOMMONCONTROLSEX);
    icex.dwICC = ICC_STANDARD_CLASSES;
    InitCommonControlsEx(&icex);

    g_himl = ImageList_Create(
    20, 20, NULL, 3, 5);

    ImageList_AddIcon(g_himl, LoadIcon(GetModuleHandle(NULL), IDI_ASTERISK));
    ImageList_AddIcon(g_himl, LoadIcon(GetModuleHandle(NULL), IDI_ERROR));
    ImageList_AddIcon(g_himl, LoadIcon(GetModuleHandle(NULL), IDI_EXCLAMATION));

    WNDCLASSEX wnd1;
    HWND MainWin;
    MSG Msg;

    wnd1.cbSize = sizeof(WNDCLASSEX);
    wnd1.style = 0;
    wnd1.lpfnWndProc = MainWindowProc;
    wnd1.cbClsExtra = 0;
    wnd1.cbWndExtra = 0;
    wnd1.hInstance = hInstance;
    wnd1.hIcon = LoadIcon(NULL, IDI_WINLOGO);
    wnd1.hCursor = LoadCursor(NULL, IDC_ARROW);
    wnd1.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wnd1.lpszMenuName = NULL;
    wnd1.lpszClassName = g_ClassName;
    wnd1.hIconSm = LoadIcon(NULL, IDI_WINLOGO);

    if(!RegisterClassEx(&wnd1)) {
        MessageBox(NULL, "Failed to register wnd1 class!", "ERROR!", MB_OK | MB_ICONWARNING);
        return -1;
    }

    MainWin = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        g_ClassName,
        "Message Box Creator",
        WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_THICKFRAME,
        CW_USEDEFAULT, CW_USEDEFAULT, 400, 350,
        NULL, NULL, hInstance, NULL);

    if (MainWin == NULL) {
        MessageBox(NULL, "Failed to create window handle!", "ERROR!", MB_OK | MB_ICONWARNING);
        return -1;
    }

    ShowWindow(MainWin, nCmdShow);
    UpdateWindow(MainWin);

    while(GetMessage(&Msg, NULL, 0, 0) > 0) {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
}