[whpalmer4]

The Contexts button actually opens a perspective named Contexts. Try instead using the Switch button (not on the default toolbar, but easily added) which simply changes the view from Project mode to Context mode (or vice versa). If you have focused on a project (or a collection of them) when you switch to Context mode, you will only see the actions from the project(s) you focused on, not all of the actions in your database.

You can also switch views with cmd-1 and cmd-2 if you prefer the keyboard.