Preface: I ran a General Exploration analysis with "Analyze OpenMP regions" enabled (among others). As I am using MSVC and its associated OpenMP implementation (instead of the Intel one), this has never done anything useful but I did not bother disabling it.
Problem: In the General Exploration Viewpoint, after digging around the profiling results for a while, I decided to see what the Grouping option "OpenMP Region / OpenMP Barrier-to-Barrier Segment / Function / Call Stack" would do. This results in "No data to show" in the grid view. However, it is impossible to change the grouping option when there is "no data to show" - I don't see why this was implemented but in this case it makes me entirely unable to switch to another grouping option to see my results again.
For avoidance of doubt: I have plenty of report data that is visible in other grouping modes (e.g. "Function / Call Stack"). I am unable to change the grouping mode, presumably because this grouping mode (and probably any related one) has no data to show.
Neither switching viewpoints (e.g. to Hardware Events and back), nor reloading/reresolving the report, nor restarting VS, nor loading another report changes this. The selected grouping mode appears to be persisted globally. This means I am entirely unable to use the General Exploration Viewpoint's Bottom Up tab in any project.
Please advise on how to restore VTune to functionality, for example by pointing out where the grouping mode is persisted so it can be changed manually. Allowing users to change the grouping mode even with no data to show would also be a welcome change to avoid this issue.
I have found a workaround: If you use the ITT API to provide user events and tasks, you can click on any task in the Summary tab and it will take you to the Bottom-up tab with the "Task Type / Function / Call Stack" grouping selected.