Some UI feedback:
* On Windows, the tab and ctrl-enter shortcuts seem to be "captured" by the node input, like you have to push them twice if you're in the middle of typing something. You can't just type "test" and tab to the next node, you have to tab-tab.
* Box-selection (drag a rectangle around one or more nodes) would be super helpful.
* When you drag a node to move it, it's not immediately obvious what will happen to it. A move "preview", like a shadow where it's going to end up, along with how the lines will change, would be awesome.
* It would be REALLY cool to be able to import/export UML (https://plantuml.com/sequence-diagram). I love the semantics of UML, but darned if it isn't hard to edit quickly. Being able to use a keyboard interface, along with maybe a quick dropdown-selection to select node type, to quickly prototype a diagram and then export it to UML when done would be something I'd be VERY willing to pay for.
* It isn't super clear to me, in this system, how the connections between nodes work. Are there different arrows, strokes, etc.? Are there different node shapes (rectangles, diamonds, circles) like traditional flowcharts that represent different types?
Overall, really cool to see this happen. Thanks for making this and looking forward to future changes!