The sidebar section is where you will navigate between applications, scans, and issues. The content display will reflect the context being viewed.
The top of the sidebar will display the currently viewed context, and also serves as a button to navigate to the previous context.
Below that you will find filtering functionality where you will be able to filter the content being displayed in the sidebar. More information on the filtering capabilities of each context can be found in the relevant Applications, Scans, and Issues sections.
If you are viewing the sidebar from the overview or application context, you will also see a "Scan new application" or "Scan new version" button.