Can Gmail Add-ons be always available in the sidebar?

Question

I am creating a Gmail Add-on (for the new look Gmail - circa May 2018), I cannot see how it is possible to have the add-on be available "all the time" on the sidebar like the Calendar / Keep and Tasks add-ons.

I can only find documentation that allows the add on to be called when an email has been clicked to provide some contextual information for that email in the sidebar.

The Add-on that I am developing is aiming to provide a service to the whole gmail inbox rather than being specifically actionable on a message.

Is it not possible at the moment or am I missing something in the manifest or elsewhere?

Answer 1

Gmail has now, by default, places all add ons on the side bar. Refer below: