Allow sorting by matrix columns

[Anonymous]

Thanks for adding % of row total.

However, it can often be used to spead the percentage by categories. E.g Accurate vs Inaccurate.

And unfortunately it is not possible to sort them A-Z. 

For example, I want to track accurate and inaccurate data. And I cannot sort by the most inaccurate origins.

Adding this option will greatly improve data visibility for category matrix users, as it will allow to sort by the most problematic/successful points.