I’m trying to create a tooltip in VBA using winapi calls, basically following the tutorial from MSDN remapped to VBA with Declare statements etc. The call to CreateWindowsEx() returns NULL and the follow-on GetLastError() returns 0 as well. I’ve tried both in Excel and Outlook, but it gives the same result. Is this simply not possible, or is there anything wrong with the parameters I pass to CreateWindowsEx()?

Here is the complete code snippet:

Private Type INITCOMMONCONTROLSEX_REC
  dwSize As Long
  dwICC As Long
End Type

Private Const ICC_WIN95_CLASSES = &HFF

Private Declare PtrSafe Function InitCommonControlsEx Lib "Comctl32.dll" (ByRef icce As INITCOMMONCONTROLSEX_REC) As Long

Private Const WS_EX_TOPMOST As Long = &H8
Private Const WS_POPUP As Long = &H80000000
Private Const TTS_ALWAYSTIP As Long = &H1
Private Const TTS_NOPREFIX As Long = &H2

Private Const TOOLTIPS_CLASS = "tooltips_class32"

Private Declare PtrSafe Function CreateWindowEx Lib "user32.dll" Alias "CreateWindowExA" (dwExStyle As Long, lpClassName As String, lpWindowName As String, _
        ByVal dwStyle As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hWndParent As LongPtr, ByVal hMenu As LongPtr, _
        ByVal hInstance As LongPtr, lpParam As Any) As LongPtr


Public Sub CreateToolTip()
    Dim ret As Long
    Dim retLng As LongPtr
    
    Dim iccRec As INITCOMMONCONTROLSEX_REC
    iccRec.dwSize = LenB(iccRec)
    iccRec.dwICC = ICC_WIN95_CLASSES
    
    ret = InitCommonControlsEx(iccRec)
    Dim wc_info As WNDCLASSEX
    wc_info.cbSize = LenB(wc_info)
    ret = GetClassInfoEx(0, TOOLTIPS_CLASS, wc_info)
        
    Dim hWndTip As LongPtr
    hWndTip = CreateWindowEx(WS_EX_TOPMOST, TOOLTIPS_CLASS, vbNullString, _
        WS_POPUP Or TTS_NOPREFIX Or TTS_ALWAYSTIP, _
        0, 0, 0, 0, 0, 0, 0, ByVal 0)

End Sub