Jack support in 1.3.13

Ubuntu 19.10. I’ve been trying to sync the transport of Synfig 1.3.13 to Jack as described in Mr Dmitriev’s 2014 video https://www.youtube.com/watch?v=NHFOyz2WjoA

I am able to sync qjackctl and Ardour, but clicking the “jack” icon in Synfig does nothing – I can watch in qjackctl’s message window as it reports seeings e.g. Ardour changing the config, but clicking Synfig’s Jack icon does nada for me,

Thanks in advance for any insights.

@KonstantinDmitriev can you check it please?