Unable to use annotate feature in Ubuntu 20.04

Solution 1:

You can use the Draw On Your Screen GNOME Shell extension.

Refer to this question on how to install GNOME Shell extensions: How do I install and manage GNOME Shell extensions?

After installing, you can toggle the extension on and off by pressing Super+Alt+D.

The extension offers a plethora of annotation settings, accessible by right-clicking with the extension enabled:

Here are some Tips and Tricks on using the extension.

Also remove the Compiz packages that you installed, as they have no use on GNOME, by running:

sudo apt-get purge compizconfig-settings-manager compiz-plugins compiz-plugins-extra

Solution 2:

This is possible with latest Ubuntu MATE 20.04 LTS.

All you need is to switch to MATE DE by

sudo apt-get update
sudo apt-get install ubuntu-mate-desktop^

Then select its session on login screen, install the Compiz-related stuff here by:

sudo apt-get install compiz compiz-core compiz-mate compiz-plugins compiz-plugins-default compiz-plugins-extra compizconfig-settings-manager

Then run MATE Tweak to select Compiz decorator on Windows tab, Window manager → Compiz.

And finally enable Annotate in the CCSM as you have planned to do. Personally I have added <Shift><Alt><Super>Button3 shortcut for Clear.

Then enjoy:

Solution 3:

Since 17.10, Ubuntu hasn't used Compiz (as part of the Unity desktop) as part of the default desktop. As such I don't think you're going to successfully use that method for annotating your screen.

We now use GNOME Shell, which uses a concept of extensions to add features to the desktop experience. One such extension is called Draw On You(r) Screen. Perhaps that could work for you?