Check Ecosystem first.
Probably not ideal, but working example. First state, listens to mousclick, goes to a new state, which has a wait action on top that goes to Finished event. Underneath the wait action, it also listens for a mouse click (which would be the double click). The wait timer must be extremely short, and when run out, it’ll go back to the first state. Thus, only if you click twice, fast, it’ll register.
What happens is that you reach the second state only on mouseclick, but it stays in that state only super-briefly, so only in that brief moment you can click again, i.e. double click to proceed.