Create segments using calculated metrics

[#1]

Description - Ability to create segment based on calculated metrics

Why is this feature important to you -  Sometimes a calculated metrics need to be used to get a more accurate segment

How would you like the feature to work - In my case, I created a metrics of revenue with tax, which added 2 existing metrics of revenue and tax.  I then would like to create a segment of visits that meet a threshold of the calculated metrics.

Current Behaviour - Calculated metrics cannot be used in segment creation.