Thanks Bernhard for the help! You are right, I am running Gnome/Wayland, and this seems to be unsupported.
- Bug#925483: tilda: does not start (segfault) Guenter Grodotzki
- Bug#925483: tilda: does not start (segfault) Bernhard Übelacker
- Bug#925483: tilda: does not start (segfault) Gunter Grodotzki