My tests shows that filtering and sorting on classification store values from grid views does not work.
I have tested this on demo environment.
- Click on a folder containing products to show the grid view.
- Add a column which comes from a classification store.
- Set filter on that column => does not work
- Set sorting on that column => does not work.
Can you tell us anything about that? Is it supposed to work? If not, are there any plans to support it?