Chrome Version       : 73.0.3635.0

What steps will reproduce the problem?
(1) Install a Mac PWA and enable chrome://flags/#create-app-windows-in-app
(2) Use Command-Option-I to open devtools
(3) Ensure the devtools window is undocked (actually, I don't see an option to dock the devtools window, is that another bug?)
(4) Close the devtools window with either Command-W or the red traffic light

What is the expected result?

The PWA window is focused

What happens instead?

The browser window is focused. If the browser window is closed, the PWA window still loses focus.

Not sure this is a M73 blocker.