I didn't see this mentioned in the sprm documentation,
but that is how MS Word seems to implement it.

Change-Id: I5b86ecf99a884e768877cdb0e71f43cdb9f2ad76
Reviewed-on: https://gerrit.libreoffice.org/59221Reviewed-by: Justin Luth <justin_luth@sil.org>
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>