Run
sudo apt-get install gnome-session-fallback
Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)
or (alias)
sudo apt-get install gnome-panel
from a terminal. Then logout to reach the logon screen and click on the options button next to you name. Select Gnome Classic, log in et voilĂ .
Gnome Classic