Official comment
In the upcoming 10.4 release, set to launch very soon, Execution Sets and Results have their own context, so it will be easier to work with and analyze the results of an Execution Set. From the top-level, when you select an Execution Set you will go into a view that is dedicated to the results of that Set with the details specific to the level of the results you are viewing. There will only ever be one tab for each Execution Set, and the label of the tab will help you understand the level and execution set; this is supported by breadcrumbs, to make it easier to navigate within the results.
If you haven't seen the preview video, you can view it in the Resource Center - lower-left of the screen - which includes links to videos, in-app guided walkthroughs, and release notes. You can also see the video here: https://youtu.be/JXRtZoJropc