Выводится лишний текст в окне winapi

Подскажите, Как исправить ввод лишних символов?

#include <windows.h>
#define ID_EDIT 1000
#define ID_COMBBOX 1001
#define ID_BUTTON 1002
BOOL RegClass(WNDPROC, LPCTSTR, UINT);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HINSTANCE hInstance;
char szClassName[] = "Combolist";
char szTitle[] = "Работа с комбинированным списком";
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    MSG msg; HWND hwnd; hInstance = hInst;
    if (!RegClass(WndProc, szClassName, COLOR_WINDOW))
        return FALSE;
    if (!(hwnd = CreateWindow(szClassName, szTitle,
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        100, 50, 364, 360, 0, 0, hInstance, NULL))) return FALSE;
    while (GetMessage(&msg, 0, 0, 0))
    {
        TranslateMessage(&msg); DispatchMessage(&msg);
    }
    return msg.wParam;
}
BOOL RegClass(WNDPROC Proc, LPCTSTR szName, UINT brBackground)
{
    WNDCLASS wc; wc.style = wc.cbClsExtra = wc.cbWndExtra = 0;
    wc.lpfnWndProc = Proc; wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(brBackground + 1);
    wc.lpszMenuName = (LPCTSTR)NULL;
    wc.lpszClassName = szName; return(RegisterClass(&wc) != 0);
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM IParam)
{
    static HWND hCombBox, hEdit, hButton, hStatic;
    int uItem; char Buf[80];
    switch (msg)
    {
        case WM_CREATE:
        {
            hStatic = CreateWindow("static",
                                   "Введите строку для ввода в список",
                                   WS_CHILD | WS_VISIBLE | SS_CENTER,
                                   30, 10, 300, 20, hwnd, (HMENU)0, hInstance, NULL);
            hEdit = CreateWindow("edit", NULL,
                                 WS_CHILD | WS_VISIBLE | WS_BORDER |
                                 ES_LEFT | ES_AUTOHSCROLL, 30, 40, 300, 30,
                                 hwnd, (HMENU)ID_EDIT, hInstance, NULL);
            hCombBox = CreateWindow("ComboBox", NULL,
                                    WS_CHILD | WS_VISIBLE | WS_VSCROLL|
                                    CBS_SIMPLE|CBS_SORT, 30, 80, 300, 200, 
                                    hwnd, (HMENU)ID_COMBBOX, hInstance, NULL);
            hButton = CreateWindow("button", "Добавить",
                                   WS_CHILD | WS_VISIBLE |
                                   BS_PUSHBUTTON, 130, 290, 100, 30, hwnd,
                                   (HMENU)ID_BUTTON, hInstance, NULL);
            SetFocus(hEdit);
            return 0;
        }
        case WM_COMMAND:
        {
            switch (LOWORD(wParam))
            {
                case ID_COMBBOX:
                {
                    switch (HIWORD(wParam))
                    {
                        case CBN_ERRSPACE:
                        {
                            MessageBox(hwnd, "Мало naмяти", szTitle, MB_OK);
                            return 0;
                        }
                        case CBN_DBLCLK:
                        {
                            uItem = (int)SendMessage(hCombBox, CB_GETCURSEL, 0, 0L);
                            if (uItem != LB_ERR)
                            {
                                SendMessage(hCombBox, CB_GETLBTEXT, uItem, (LPARAM)Buf);
                                MessageBox(hwnd, (LPSTR)Buf, szTitle, MB_OK);
                            }
                            return 0;
                        }
                        default: return 0;
                    }
                    return 0;
                }
                case ID_BUTTON:
                {
                    SendMessage(hEdit, EM_GETLINE, 0, (LPARAM)Buf);
                    SendMessage(hCombBox, CB_ADDSTRING, 0, (LPARAM)Buf);
                    SetWindowText(hEdit, "\0");
                    SetFocus(hEdit);
                    return 0;
                }
                default:return 0;
            }
        }
        case WM_DESTROY: { PostQuitMessage(0); return 0; }
    }
    return DefWindowProc(hwnd, msg, wParam, IParam);
}