Not really a problem for here, just to notify upstream so as to try and create pressure for downstream.

Tilix is broken on Debian Sid as of 2017-09-23. cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=%23876479

I'd suggest this is a gtkd-3 packaging problem rather than a tilix problem. Repackage gtkd-3 then tilix, and hopefully problem solved.