Dan,
In response to your queries:
1) Other browsers such as firefox, IE8, and chrome show increased memory usage over a period of time using the scheduler, but this isn't performance affecting (or not as obvious as in IE6/7).
2) The issue occurs even if there are no events shown on the scheduler, just a number of resources (say 50), and their working hours (calculated via an event handler). Memory usage increase per postback can be as much as 10mb.
3) We don't use dynamic event loading - this option causes the memory load to increase as before, but has the side-effect of not showing any working hours for resources.
The main issue is performance degradation on IE6 and memory usage (e.g. not releasing the memory) in IE7. We had update panels doing async postbacks, but these had to be removed because updates were taking 2+ minutes on IE6 (initial load was in the region of 10-20 seconds)
Customer reports overall application performance becomes unusable after a period of 1-2 hours work, which we need to rectify before the app can go live.
Regards,
Paul