In Analysis Workspace, I created a freeform panel to report occurrences of our particular eVar33 (displayed as in rows), over 3 discrete time periods (displayed as columns). I then selected multiple rows in that report to highlight, and from those rows right-clicked to Visualize -> Donut the results, showing 3 donut charts (one for each time period).
I have routinely saved this workspace, and while the freeform panel renders when I open the file, the visualization pane appears - only blank.
Anyone having difficulty retaining donut visualizations?
I tried reproducing the report as you described and saved it with the donut graphs. It is saving on my end with the selection that I did and also displaying the donut graph correctly. Could you please try making the project again and see if the issue is re-surfacing?