When you set up a historic segment the process is counter intuitive

* To apply a segment on a go forward basis I just select it
* But to do it historically I have to add the segment, scroll down and click into the "modify" and make the change
This inconstancy is confusing.

I would expect to just be able to set the report to my historic period and pick the segment and have it start processing for that historic time period.

When the historic segment starts to process NOTHING tells you that it is processing. The report looks like you have the segment applied, because you can see the segment name on the right hand menu, but the data is still All Visitors

IBM should immediately return you to the screen that tells you that the segment is processing and not show you misleading data.