Could it be that the CPU usage engendered by the loop leaves too little over for external cosmetics?
Indeed, the phenomenon is part of OS9 (threading, timeslicing, asymmetrical (unpredictable) division of processor capacity over applications)
In some cases one of these works perfectly, but in a different context not at all. To my mind most of this is ad hoc “working around” rather than good scripting.
There is no true solution on a scripting level: scripting depends on these mechanisms. Wait for OS X to become a viable scripting platforms, in the next few ages…
Best workaround: a combination of what you describe, make your scripting the most demanding app in the system.
So did I.
Eelco, what sort of things had you in mind when you wrote “make your scripting the most demanding app in the system”?