You can place an "anchor" either on a resource within the Workbench, or at a specific line within a file, by creating a bookmark. Then you can use the Bookmarks view to return to those files quickly.

The Bookmarks view (Window > Show View > Bookmarks) displays all bookmarks that you have created.

Tasks view Creating a bookmark for an entire file
Creating a bookmark within a file
Deleting a bookmark
Adding line items in the Tasks view
Associating a task with an editable resource Markers
Tasks view
Problems view
Bookmarks view