I'd like to view my history in tree form with the site listed and details collapsed. Once I find the right site then I can open it to view the details. I managed to find how to change this by accident on one computer but I cant find it again.
click Ctrl+Shift+H to open Library window OR from Firefox button > History > show all history
then see : Viewing the browsing history - Firefox
Thank you, that's exactly what I was looking for.