Noob problem with group box

[Waterfox]

This is most likely a really simple fix. I have the code below in my main windows WM_CREATE case but for some reason there's no options in the combo box, it's just blank, but I'm hoping to see "test1" and "test2" in it. I'm sure I'm missing something really simple, what am I doing wrong?

HWND Test; 
       Test = CreateWindow( L"COMBOBOX", L"", 
        WS_CHILD | WS_VISIBLE | CBS_DROPDOWNLIST, 
        8, 176, 105, 21, Panel1, (HMENU)GROUPBOX_TEST, GetModuleHandle(NULL), NULL);
	SendMessage(Test, CB_ADDSTRING, 0, (LPARAM) "test1");
	SendMessage(Test, CB_ADDSTRING, 0, (LPARAM) "test2");