VS Addin: QMap in autoexp.dat

From the autoexp file.

;------------------------------------------------------------------------------
; QMap
;------------------------------------------------------------------------------
QMap<*>{
preview
(
#(
"[", $e.d->size, "](",
#tree
(
head: $c.d->forward,
size: $c.d->size,
left: backward,
right: forward
) : $e, ")"
)
)

children
(
#tree
(
head: $c.d->forward[0],
skip: $c.d,
size : $c.d->size,
left : backward,
right : forward
) : ( (QMap<$T1>::Node*)((char*)&$e - (sizeof((QMap<$T1>::PayloadNode)0) - sizeof(QMapData::Node*))) )
)
)
}

Expected to see:
QMap variable value don't display in watch window. It display (error).