You can only add a user if the corresponding transport request exists in the folder Modifiable.
You can create a new task to add users to a transport request. Consequently, you can ensure split development activities amongst several users and ensure that a transport request can only be released if all involved users have finished their work.
You cannot create a transport request within the Transport Organizer view of ABAP Development Tools for SAP NetWeaver. However, if you create or edit a development object, you can create a transport request within the corresponding wizard.
The new task is created in the Transport Organizer view and the corresponding transport request is assigned to the user who is logged on. The task is also opened in the integrated SAP GUI- based Workbench.