About working sets
A working set enables you to group projects together and display a smaller subset of projects.
The Project Explorer view usually displays a full list of all your projects associated with the current workspace. If you have a lot of projects it can be difficult to navigate through the list to find the project that you want to use.
To make navigation easier, group your projects into working sets. You can select one or more working sets at the same time, or you can use the Project Explorer View Menu to switch between one set and another. To return to the original view, select the Deselect Working Sets options in the View Menu.
Working sets are also useful to refine the scope of a search or build projects in a specific working set.