Custom navigation menu area defined in plugin


I am currently writing a new plugin that has its own page handler and custom display template. The template needs to have a custom navigation in the sidebar.

In order to add a new menu area, in a custom theme, I would normally expect to be able to use something like:


However I only want the menu to be defined by the theme IF my custom plugin is also loaded.

How would I check within my theme plugin if my custom plugin is loaded? I’ve been looking for an example but have failed.

If it is possible to add a custom navigation area from within a generic plugin then that would be useful too - is there a way to do that, or should new menu areas always be defined in the theme and not the plugin?

Application Version - e.g., OJS 3.1.2:

Many thanks in advance.