Because highly interactive programs require frequent communication between the client and server, they are not practical for thin client configurations deployed over wide-area networks like the Internet. The more interactive the program, the slower the performance is over slow connections.
If your program was coded with event procedures (handlers), for instance, you should consider removing all but the events that your program really cares about, because event procedures result in frequent "calls" from the UI layer back to the COBOL layer. If your program tracks mouse movements or watches for interactions with controls, you may want to make further modifications. You can choose to redesign the screen or you can just simplify your program's interaction with the screen. The goal is to reduce the number of times that the client and server have to communicate.