Explain the problem as you see it
In a search node, when viewing results in a grouped view, it will show all possible options even when there are no results for that particular group. Both in list and in card view, this results in a lot of clutter and unused space in the UI. For instance, when I have tasks grouped by project some projects might not have tasks. These projects are still shown as a title in the list, or as an empty column in card view. The same goes for the ever present "not defined" category. There is no possibility to hide unused options.
Why is this a problem for you?
I use search nodes to create overviews of my work and grouping is really powerful, but when there are some unused group titles it creates clutter that works against the overview I'm trying to achieve.
Suggest a solution
Have an option to hide unused group items, preferably per search node. In some cases you want this behavior, in others not. The most logical location would be in the dropdown where you select the "group by" options.