How to use a compositor to improve window manager performance and redrawing, but without adding any visual effects or animations.

For this, the picom compositor is a good solution. It can be ran by simply issuing a single command:

picom

Or it can be configured to start automatically.

For openbox, add this to ~/.config/openbox/autostart:

picom &

For i3, add this to ~/.config/i3/config:

exec --no-startup-id picom

For me, simply starting it solved a redrawing problem in Unity - when browsing the menus, the main window area was not redrawn without a compositor running.

However, I noticed some unnecessary visual effects or animations which came with the compositor - e.g. the menus in GIMP had some transparency set, which made them less readable.

To disable the effects, create an empty ~/.config/picom/picom.conf file - otherwise, picom may take the global configuration (defined in /etc/xdg/picom.conf) which actually explicitly enables some effects.