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Calculation of Resolution Time for defects which have been marked as Deferred

I calculate the Resolution Time of a defect by subtracting the Creation date from the Resolution date field values. This works fine in the normal defect workflow moving from New, Resolve, Validate, Closed.
One answer

Hi, Maxim
I think you would need to save the date to a custom attribute(such as a hidden attribute) when the state is set to 'deferred' and then use calculation javascript to calculate further.
There are many posts in forum on how to do similar things, such as
https://jazz.net/forum/questions/213456/capturing-the-date-when-state-changes-in-rtc
https://jazz.net/forum/questions/168883/set-workflow-stateaction-via-javascript