Non-rendered EBU-TT-D line-padding before and after <br/> inside <span>

Created by: TobbeMobiTV

EBU-TT-D has a nice line-padding feature with half-a-character padding being specified as ebutts:linePadding="0.5c"

Annex D of https://tech.ebu.ch/docs/tech/tech3380.pdf shows how this padding should work on both lines if there is a <br/> element inside a span (<span> ... <br/> ... </span>). However, currently that is not how it is rendered but there is only padding at the beginning of the first line and at the end of the second line.

To reproduce, use sample/ttml-ebutt-sample.html with the test_content http://vm2.dashif.org/dash/vod/testpic_2s/xml_subs.mpd

The sequence <span>...</span><br/><span>...</span> is rendered correctly.