Dash to Panel not showing running indicator for Nautilus
Solution 1:
I spent a few months with this problem, and finally found a solution. Set:
gsettings set org.gnome.shell.extensions.dash-to-dock isolate-locations false
and log out of/log back in to your gnome session. After this, nautilus will work correctly in the taskbar.
Found the solution here:
https://github.com/home-sweet-gnome/dash-to-panel/issues/1500#issuecomment-975520406