Figure 8.1 shows the progress dialog that is displayed when the Compute button is pressed. Although in this case the computation is fairly quick, finishing in seconds, more complex computations, especially on the entire composition, can last considerably longer. There are times when you need to leave it to do a computation, and then come back sometime later to see how it is getting on. We ourselves (Roo and Joey) use advertising breaks in TV programs to hop in and check on progress.