It would be nice to be able to deactivate a state instead of having to deactivate the actions inside the state one by one.
A deactivated state would act as if it didn't have any action inside, or if all of them were inactive.
Somehow, the information about a or one more states being deactivated should be displayed somewhere so the user doesn't forget about them; first and foremost in the FSM itself. It should warrant a warning in the log too (but could be deactivated in the preferences). Perhaps a supplementary function could be added to the Tools window so as to display the number of deactivated and cycle through them (previous, next), perhaps displaying a quick list of the first three ones.
A deactivated state would have its appearance changed, perhaps with a semi-opaque overlay of oblique bands as if it were in repairs?
A "warning sign" notification could displayed in the top corner of the state too.