I've seen that, so that means I need to rebuild the project every time I add something?
No you don't have to rebuild the whole project anytime you want to add something. The editor is just Javascript code, so even if you use the downloaded binary, the source is still visible in it (src folder). It's mostly there but I'm doing a bunch of QOL stuff at the moment before going to add more features.
For myself I am using the source version, and I open the app with the shell script to do live editing/testing of the editor. On windows it would be the .bat file.