I didn’t know that the connectors automatically draw lines from box to box! For years, I’d been seeking software that could do this. The line-connecting behavior is a bit weird and unpredictable, but it’s still fun!
Check out Dia.
It’s excellent. Auto layout. Connector types. Etc etc.
It’s great until you realize that it doesn’t have some specific types of connectors you need or a way to control connectors path (you can’t have connectors that go around other boxes).
My family tree (bush, thicket) is the ongoing effort of my uncle, started roughly 30 years ago. There are nearly 130,000 individuals in it.
We are migrating his data from The Master Genealogist (TMG) to Geneweb. That is quite a long story 8)
You might like to look into Webtrees.
Geez, I can’t imagine how gigantic such a tree is!