How do I prevent Chrome developer tools from closing when the current browser window closes?

Not a perfect solution, but you can add breakpoints on the events Window.close and unload by turning on the checkboxes at:

Developer tools -> "Sources" tab -> Event Listener Breakpoints -> Window -> close

And

Event Listener Breakpoints -> Load -> unload

Try to mark both and see which one works best for you

Another option is to manually add a breakpoint yourself. Open up your closes-too-quickly window, open up JS console, and:

window.addEventListener('unload', function() { debugger; })

But it all comes down to exactly what the window is doing, and when exactly you want to stop things, so experimenting with Event Listener Breakpoints in the Sources tab, as in @jfhfhf839's answer, is a good idea too.

In my case (debugging Google OAuth flow), neither Window -> Close nor Load -> Unload did the trick, but Script > Script First Statement was useful, though I had to resume execution a few times before I got to where I wanted.

Try using remote debugging: https://developers.google.com/chrome-developer-tools/docs/remote-debugging In this case Developer Tools will be opened in a separate browser tab that won't be closed automatically.

Also consider setting a breakpoint in the code that closes the window if you can find it.