In the Legacy app, it used to be possible to go to the "show" menu and select multiple contexts to view. The Next Gen app has never had that and should. I often have to use the legacy app for this functionality. However, the Show by Context feature appears to be broken in the legacy app now. Only 'none' shows for selection, and viewing a task does not show the Context assigned (as verified in the web UI)
This functionality still works in the browser, so I assume this change is not intentional.