Somebody upvoted my question today. So maybe they are looking for the answer. I posted it on autohotkey.com forums back then, and I get the answer there.
https://autohotkey.com/boards/viewtopic.php?t=21274
ControlGet, hClock, Hwnd,, TrayClockWClass1, ahk_class Shell_TrayWnd ; https://autohotkey.com/board/topic/70770-win7-taskbar-clock-toggle/
if (hClock) {
VarSetCapacity(IID_IAccessible, 16), DllCall("ole32\CLSIDFromString", "WStr", "{618736e0-3c3d-11cf-810c-00aa00389b71}", "Ptr", &IID_IAccessible)
if (DllCall("oleacc\AccessibleObjectFromWindow", "Ptr", hClock, "UInt", OBJID_CLIENT := 0xFFFFFFFC, "Ptr", &IID_IAccessible, "Ptr*", accTrayClock))
return
VarSetCapacity(variant, A_PtrSize == 8 ? 24 : 16, 0), NumPut(VT_I4 := 3, variant,, "UShort")
if (A_PtrSize == 4) ; https://autohotkey.com/boards/viewtopic.php?p=111355#p111355
DllCall(NumGet(NumGet(accTrayClock+0)+25*A_PtrSize), "Ptr", accTrayClock, "Int64", NumGet(variant, 0, "Int64"), Int64, NumGet(variant, 8, "Int64")) ; IAccessible::DoDefaultAction
else
DllCall(NumGet(NumGet(accTrayClock+0)+25*A_PtrSize), "Ptr", accTrayClock, "Ptr", &variant) ; IAccessible::DoDefaultAction
ObjRelease(accTrayClock)
}