Performance Tab - Distinguish between training types

On the performance tab of the athlete profile, I have an issue with the Duration bar chart:

When an athlete does two sessions in one day eg weights and cardio, the duration shows the total time. It does not distinguish between exercise mode durations. If this could be edited to show me some how that the total time is spread between two different sessions it would be great. Other wise i think the athlete has done too much, or forgot to stop their watch.