At some point Process Explorer started recording the CPU/memory usage graphs for a process only the moment you opened the details window for that particular process for the first time.

So even if Process Explorer had been running in background all the time, you could no longer inspect a process's CPU/memory usage history after the fact if you hadn't by chance already opened its details window before.

As the last version (I might have even asked on the forum about it, but never got a definitive response whether this was intentional or a bug) of Process Explorer that didn't exhibit this annoying new behaviour stopped working after switching to Windows 10, I switched to ProcessHacker at that point.

I've initially missed Process Explorer's miniature system information diagrams in the toolbar a little, but otherwise I've been happy with ProcessHacker.