GetClassName instead of WinGetClassList vs for ToolTips controls

Hi,

There is some discussion about tooltips content on 
http://www.autoitscript.com/forum/index.php?
showtopic=33677&st=420&start=420

I've written following script to get tooltips content:
#include <GUIConstants.au3>
Global $A_Btn, $B_Btn, $A, $B
GUICreate("Default Buttons", 300, 300)
Global $ttXprev=0,$ttYprev=0

Opt("WinTitleMatchMode", 4)

Dim $hTT=''

$Tab = GUICtrlCreateTab (10, 10, 280, 280)
$A = GUICtrlCreateTabitem ("A")
$A_Btn	= GUICtrlCreateButton ("OK", 20, 200, 100, 20)
GUICtrlSetTip($A_Btn,"Button on Tab A")
$B = GUICtrlCreateTabitem ("B")
$B_Btn	= GUICtrlCreateButton ("OK", 20, 200, 100, 20)
GUICtrlSetTip($B_Btn,"Button on Tab B")

;Init buttons state
GUICtrlSetState($A_Btn, BitOr($GUI_ENABLE, $GUI_DEFBUTTON))
;GUICtrlSetState($B_Btn, $GUI_DISABLE)

GUICtrlCreateTabitem ("")
GUISetState ()
While 1
    $msg = GUIGetMsg()
        If WinExists('classname=tooltips_class32') Then
	    $hTT = WinGetHandle('classname=tooltips_class32')
	    if $hTT <> '' then HandlerToolTips($hTT)
        endif
    Select 
    case $msg = $GUI_EVENT_CLOSE
	ExitLoop
    case $msg = $Tab
	If GUICtrlread ($Tab) = 0 then 
		GUICtrlSetState($A_Btn, $GUI_ENABLE+$GUI_DEFBUTTON)
		GUICtrlSetState($B_Btn, $GUI_DISABLE)
	else 
		GUICtrlSetState($A_Btn, $GUI_DISABLE)
		GUICtrlSetState($B_Btn, $GUI_ENABLE+$GUI_DEFBUTTON)
	endif
    case $msg = $A_Btn
	MsgBox(0,"","This is A_Btn")
    case $msg = $B_Btn 
	MsgBox(0,"","This is B_Btn")
    endselect
Wend

;=============================
; Handler of tooltip appearance
func HandlerToolTips($hTT)
local $ttX,$ttY, $state

 $ttSize = WinGetPos($hTT)
 $ttX = $ttSize[0]
 $ttY = $ttSize[1]
 $state = WinGetState($hTT) 
 if $ttX = $ttXprev and $ttY = $ttYprev then return
 if Not BitAnd($state, 2) then return
 $Title = WinGetTitle($hTT)
 $ClassNameByAPI = GetClassName($hTT)
 $ClassNameByAutoIt = StringSplit(WinGetClassList($hTT),@LF)
 $Line = ''
 $Line &= 'Title = ' & $Title & @CrLf
 $Line &= 'ClassNameByAPI = ' & $ClassNameByAPI & @CrLf
 $Line &= 'ClassNameByAutoIt = ' & $ClassNameByAutoIt[1] & @CrLf
 MsgBox(0, 'Tooltip Info', $Line)
 $ttXprev = $ttX
 $ttYprev = $ttY
endfunc

;=============================
Func GetClassName($hWnd)
Local $aResult, $Length, $stText, $Text
  $Length = 4096
  $stText = DllStructCreate ("char[" & $Length & "]")
  $aResult = DllCall("User32.dll", "int", "GetClassName", "hwnd", 
$hWnd, "ptr", DllStructGetPtr($stText), "int", $Length)
  $Text = DllStructGetData($stText,1)
  $stText = 0
  return $Text
EndFunc

Move mouse pointer over button to view message box. 
You can get content of Button's tooltips. But I found that 
WinGetClassList can't return known class name of tooltips. 
As you can see script uses other function GetClassName to get class 
name of tooltip - 'tooltips_class32'. 

Is it bug in AutoIt?

Valery