Thanks for suggestions.
I tried Guest session and a new user. Looks the same - no panel.
I used Synaptic Package handler and searched for gnome shell.
gnome-shell-common was already installed. I installed gnome-shell and
restarted, but can see no difference.
Should I install gnome (says Full GNOME desktop in description)? Do I need to
uninstall the current, standard desktop environment?
My guess is that the panel is in place and working, but Trisquel cannot show
the whole desktop, and it is not possible to scroll. With other resolutions,
Trisquel does not scale the desktop, but shows smaller parts of it magnified.
No scrolling is possible. The retina resolution is 2880 x 1800.
Is it possible to see what graphic card and driver Trisquel uses?
