e.g fdo58094-1.mml

since...

commit 13894996
Date:   Sat May 4 21:46:31 2019 +0200

    handle empty Rectangle better in starmath

Change-Id: I01d11352b8bc9f6dcf6d6565fa41b84d549f620f
Reviewed-on: https://gerrit.libreoffice.org/71963
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>