In macOS Activity Monitor, why is “Applications in last 12 hours” grayed out / disabled?

Question

Any idea why the "Applications in last 12 hours" is disabled in the "Activity Monitor"?

At one point it appeared briefly -- but after days of using it, it has since disappeared.

Using macOS 10.15.2. Many thanks.

Answer 1

It's only available on the Energy tab.

I can just tell from your pic, you're on the Disk tab.