Ubuntu dock icons on GNOME 3: show little dots instead of red underline

Previously, my dock icons showed several little red dots on their left side whenever I opened several instances of an application. I liked this feature because I could immediately tell that I had several instances, for example browser windows, running.

Now, I have only a red dash underneath the icon which tells me that one or maybe several instances are open. Is there anyway to get the 'little red dots' feature back?

I already applied

gsettings set org.gnome.shell.extensions.dash-to-dock click-action 'previews'

That's a nice feature but I am still missing the little red dots.

I am using GNOME 3.28.2 on Ubuntu 18.04.4 LTS.