I am using IntelliJ Idea 2017.3 latest release in Ubuntu 2017.10 and shortcut Ctrl+Alt+Left/Right doesn\'t work.
Whereas from
The right setting is combinations of already posted answers. To sum up:
1. Remove key bindings of Ctrl+Alt+Right/Left to GNOME enviroment
In terminal run:
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-left "[]"
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-right "[]"
2. Assigne the bindings to Forward / Back actions in Idea IntelliJ
If you use Keymap setting based on GNOME keymap the defaults for Forward / Back actions are not Ctrl+Alt+Right/Left. It must be setted.
In Idea IntelliJ menu
File | Settings | Keymap
search for
Main menu - Navigate - Forward
click on edit shortcuts and set it to Ctrl+Alt+Right
then search for
Main menu - Navigate - Back
click on edit shortcuts and set it to Ctrl+Alt+Left
Works on versions: Ubuntu 18.04.3 LTS Idea IntelliJ 2019.2.3