Multiple User Environments
When more than one Composer user attempts to log into the same Workspace, the following message appears: Workspace in use or cannot be created, choose a different one. Whenever Composer uses a Workspace, it locks the Workspace so other Composer instances cannot access it. A Workspace is meant to be a "private" development area, until the developer decides to share it with the team. It is not possible to share a single Workspace among multiple users, so you need to set up (private) workspaces for each developer. To merge the work of different developers together, use source control, which could be be SVN (Subversion), Git, or something else. This is the best way to manage a Composer Project with multiple users working simultaneously on it, and prevent the developers from interferring with each other's work.
You could consider the Subversion plugin in Composer as a connector to source countrol like SVN. To install the Subversion plugin, see Software Updates Functionality (Plugins).
Continuing with this example, once the Subversion plugin is installed, the Project can be shared using source control. When you right-click on a Project, you will find all the relevant options under the Team menu. For the first time, a Project needs to be shared with source control. After this, there will be options on the Team menu.