A method and system for managing data (i.e., objects) that are shared by multiple instances of a shared application program. A shared application program is an application program that is executing simultaneously on multiple computers and that has a copy of data that is being shared by each instance of the application program. In particular, each computer maintains a copy of the shared data. When an instance of the application program modifies the shared data, the modifications are sent to the other computers. Each of these other computers stores the data in its copy of the shared data, and each instance of the application program updates its user interface to reflect the modifications to the shared data. Thus, the users of the shared application program can cooperatively modify and view the shared data. For example, multiple users can be executing a word processing program on their computer and sharing a common document. As one user changes the document, the word processing program updates its copy of the shared data. The changes are then transmitted to the other computers so that their copy of the shared data can be updated. In particular, an object management (OM) system is provided that enables shared application programs to manage their copy of the shared data. Each computer has a copy of the OM system. The OM system, under the direction of the shared application program, manages the adding, deleting, and modifying of the shared data. The OM system also controls the transmitting of modifications to the copy of the shared data to the other computers.