macOS Activity Monitor – How to Show Command of a Process

In Activity Monitor there is a dropdown menu in the top of the window. My Processes was selected. Changing it to All Processes solved the issue.

Not really. The thing is, most of the time, processes in Activity Monitor don't actually have a UI that you can 'switch' to. Using the Google Chrome example, think of those 'Google Chrome Renderer' processes as background tasks, and you just see the result of them in the main 'Google Chrome' process. Activity Manager does not have a way to identify how to tie these 'background tasks' to the parent GUI.

However, for your particular problem, Google Chrome actually provides you with a Task Manager that will help you out:

In many ways, the task manager is like a hospital monitor: you can use it to track the performance of its internal processes. If the browser seems to be sluggish, open the task manager to find details about each active process and close the one that seems to be using up a lot of resources.

You can use this to identify which tab is using up too many system resources. You can also use the Process ID from the Chrome Task Manager to match the process up in Activity Monitor (Process ID == PID).