The invention is directed to techniques for communicating messages between windows or frames in a computer display. A computer system suited for use with the invention includes a computer display providing a source window and a target window, as well as respective source display code and target display code associated with each window. A messaging module coordinates the communication of messages and supports a database of target identifiers that identify windows, functions, and message handlers associated with the windows. The source display code originates a message with selection information and provides the message to the messaging module, which uses the selection information to determine which window to send the message to based on the target identifiers in the database.