I posted the following earlier to the Squeak list but didn't get a responce. Hopefully someone on the Pharo list can help me. I need this information so I can make some planned changes to the ProgressDisplay package I released a while back. ----------------------------------------------------------------------------------------------------------------- A SystemProgressMorph is used to display progress while some computation is being done. Furthermore the progress bars can be stacked to show progress of component computations within a computation. This I understand and understand most of the code. But not All. What I have trouble with is understanding why a ProgressInitiationException is needed. In particular, String>>displayProgressAt:from:to:during: does: ProgressInitiationException display: self at: aPoint from: minVal to: maxVal during: workBlock. This method sets a few variables and then does: ^self signal This signal is caught where upon a SystemProgressMorph is started or extended with an additional progress bar. But I don't understand why sending a signal to a ProgressInitiationException is needed to get the ball rolling, Can someone please explain why things are done the way they are? Regards, Ralph Boland