We've had a couple of reports of Indigo crashing when adding a new stack. I'm believe we may have managed to identify the circumstances around that; if you add a new stack and:
- the system stack is selected and
- you currently have no other stacks
...then we see the crash. If you're having this crash please let me know whether the circumstances above are the same for you.
I've replicated this and will have a fix in the next release. In the meantime you can work around it by deselecting the System Stack (click anywhere below it) before adding a new stack.