> UI-wise, I'm not sure why it looks like an installable component rather than a separate checkbox. Is it a limitation of the installation software?

I originally did it as a separate check box UI-wise but couldn't hook that into be an actual "Feature" in MSI terms. The way it's currently done allows it to be added to certain tables, allowing us to conditionally modify the "Environment" table which contains the optional path addition.

I am by no means an MSI expert. This is just the way Martin and I talked about it at PyCon and the way I've seen it done around the web. If there's a way to tie a checkbox to the Feature table, I would like that.