I have a long list of benchmarks to chose from in the aggregator. The bottom 2 have many problems and solver configs, so I want to expand those, but I don't want to expand the older benchmarks (as they are historic benchmarks that I don't want to delete but only rarely need). Now, everything gets expanded, which is not a clear experience and requires lots of scrolling.

Change the expand/collapse buttons so they only expand/collapse the selected item. If nothing is selected, behave as expand/collapse all (so don't disable the button in that case).