Listview Group WM_NOTIFY trigger ?

#include <GUIConstantsEx.au3>
#include <GuiImageList.au3>
#include <GuiListView.au3>
#include <WindowsConstants.au3>
#include <MsgBoxConstants.au3>
 
Func WM_NOTIFY($hWnd, $iMsg, $wParam, $lParam)
    #forceref $hWnd, $iMsg, $wParam
    Local $tInfo, $tNMHDR = DllStructCreate($tagNMHDR, $lParam), $hWndFrom = HWnd(DllStructGetData($tNMHDR, "hWndFrom"))
    Local $iIDFrom = DllStructGetData($tNMHDR, "IDFrom"), $iCode = DllStructGetData($tNMHDR, "Code")
    Switch $hWndFrom
        Case $hWndListView
            Switch $iCode
 
            ;   Case $of?????? ; A Group was clicked       <---- I need help with this
 
 
                Case $LVN_COLUMNCLICK ; A column was clicked
                    $tInfo = DllStructCreate($tagNMLISTVIEW, $lParam)
                    _DebugPrint("$LVN_COLUMNCLICK" & @CRLF & "--> hWndFrom:" & @TAB & $hWndFrom & @CRLF & _
                            "-->IDFrom:" & @TAB & $iIDFrom & @CRLF & _
                            "-->Code:" & @TAB & $iCode & @CRLF & _
                            "-->Item:" & @TAB & DllStructGetData($tInfo, "Item") & @CRLF & _
                            "-->SubItem:" & @TAB & DllStructGetData($tInfo, "SubItem") & @CRLF & _
                            "-->NewState:" & @TAB & DllStructGetData($tInfo, "NewState") & @CRLF & _
                            "-->OldState:" & @TAB & DllStructGetData($tInfo, "OldState") & @CRLF & _
                            "-->Changed:" & @TAB & DllStructGetData($tInfo, "Changed") & @CRLF & _
                            "-->ActionX:" & @TAB & DllStructGetData($tInfo, "ActionX") & @CRLF & _
                            "-->ActionY:" & @TAB & DllStructGetData($tInfo, "ActionY") & @CRLF & _
                            "-->Param:" & @TAB & DllStructGetData($tInfo, "Param"))
                    ; No return value
                Case $NM_CLICK ; Sent by a list-view control when the user clicks an item with the left mouse button
                    $tInfo = DllStructCreate($tagNMITEMACTIVATE, $lParam)
                    _DebugPrint("$NM_CLICK" & @CRLF & "--> hWndFrom:" & @TAB & $hWndFrom & @CRLF & _
                            "-->IDFrom:" & @TAB & $iIDFrom & @CRLF & _
                            "-->Code:" & @TAB & $iCode & @CRLF & _
                            "-->Index:" & @TAB & DllStructGetData($tInfo, "Index") & @CRLF & _
                            "-->SubItem:" & @TAB & DllStructGetData($tInfo, "SubItem") & @CRLF & _
                            "-->NewState:" & @TAB & DllStructGetData($tInfo, "NewState") & @CRLF & _
                            "-->OldState:" & @TAB & DllStructGetData($tInfo, "OldState") & @CRLF & _
                            "-->Changed:" & @TAB & DllStructGetData($tInfo, "Changed") & @CRLF & _
                            "-->ActionX:" & @TAB & DllStructGetData($tInfo, "ActionX") & @CRLF & _
                            "-->ActionY:" & @TAB & DllStructGetData($tInfo, "ActionY") & @CRLF & _
                            "-->lParam:" & @TAB & DllStructGetData($tInfo, "lParam") & @CRLF & _
                            "-->KeyFlags:" & @TAB & DllStructGetData($tInfo, "KeyFlags"))
                    ; No return value
 
            EndSwitch
    EndSwitch
    Return $GUI_RUNDEFMSG
EndFunc   ;==>WM_NOTIFY
 
Func _DebugPrint($s_Text, $sLine = @ScriptLineNumber)
    ConsoleWrite( _
            "!===========================================================" & @CRLF & _
            "+======================================================" & @CRLF & _
            "-->Line(" & StringFormat("%04d", $sLine) & "):" & @TAB & $s_Text & @CRLF & _
            "+======================================================" & @CRLF)
EndFunc   ;==>_DebugPrint
 
If Not StringInStr($CmdLineRaw, "/ErrorStdOut") Then Exit MsgBox($MB_TOPMOST, @ScriptName, 'please run from the editor, thanks', 10)
 
Global $idListview, $hWndListView
Example()
 
Func Example()
    Local $aInfo, $hImage, $idListview
 
    GUICreate("ListView Group COLLAPSIBLE", 400, 300)
 
    $idListview = GUICtrlCreateListView("", 2, 2, 394, 268)
    $hWndListView = GUICtrlGetHandle($idListview)
    GUISetState(@SW_SHOW)
 
    ; Load images
    $hImage = _GUIImageList_Create()
    _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0xFF0000, 16, 16))
    _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0x00FF00, 16, 16))
    _GUIImageList_Add($hImage, _GUICtrlListView_CreateSolidBitMap($idListview, 0x0000FF, 16, 16))
    _GUICtrlListView_SetImageList($idListview, $hImage, 1)
 
    ; Add columns
    _GUICtrlListView_AddColumn($idListview, "Column 1", 100)
    _GUICtrlListView_AddColumn($idListview, "Column 2", 100)
    _GUICtrlListView_AddColumn($idListview, "Column 3", 100)
 
    ; Add items
    _GUICtrlListView_AddItem($idListview, "Row 1: Col 1", 0)
    _GUICtrlListView_AddSubItem($idListview, 0, "Row 1: Col 2", 1)
    _GUICtrlListView_AddSubItem($idListview, 0, "Row 1: Col 3", 2)
    _GUICtrlListView_AddItem($idListview, "Row 2: Col 1", 1)
    _GUICtrlListView_AddSubItem($idListview, 1, "Row 2: Col 2", 1)
    _GUICtrlListView_AddItem($idListview, "Row 3: Col 1", 2)
 
    ; Build groups
    _GUICtrlListView_EnableGroupView($idListview)
    _GUICtrlListView_InsertGroup($idListview, -1, 1, "Group 1", 1)
    _GUICtrlListView_SetGroupInfo($idListview, 1, "Group 1", 0, $LVGS_COLLAPSIBLE + $LVGS_COLLAPSED) ; <---
    _GUICtrlListView_InsertGroup($idListview, -1, 2, "Group 2")
    _GUICtrlListView_SetGroupInfo($idListview, 2, "Group 2", 0, $LVGS_COLLAPSIBLE + $LVGS_COLLAPSED) ; <---
    _GUICtrlListView_SetItemGroupID($idListview, 0, 1)
    _GUICtrlListView_SetItemGroupID($idListview, 1, 2)
    _GUICtrlListView_SetItemGroupID($idListview, 2, 2)
 
    GUIRegisterMsg($WM_NOTIFY, "WM_NOTIFY")
 
    ; Loop until the user exits.
    Do
    Until GUIGetMsg() = $GUI_EVENT_CLOSE
 
    GUIDelete()
EndFunc   ;==>Example