The topic http://forums.adobe.com/message/3896291#3896291 mentions very poor performance on event handling on Oct 15, 2011.
After 6 months there seems to be no fix or workaround provided by Adobe, not even a notice that the issue is confirmed.
The bug referenced in that thread, AIR browser is slow to load AJAX app, is still open/to track. Based off the notes from Jian on Nov 6th, we've been able to reproduce the issue but it does not have enough votes to qualify for our current releases. We need additional users to cast their votes that this is impacting their applications.
There is a note on November 11th, that suggests that removing inset box shadows can resolve this issue in some cases. This is most likely similar to other known bugs where -webkit-box-shadow impacts performance on Windows. All cases have been deferred at this time as the solution is not trivial to address (I've personally entered this bug at least twice.)
Chris, thanks for helping us keep this performance issue alive and tracked - much appreciated.
In my case, the Windows Adobe AIR performance problem in my application has nothing to do with CSS box shadows --- I didn't use box shadows in the app.
Thanks for the info that at least in your case, css shadows are not involved. I've just commented in the bug report and cast my vote. Please spread the word and ask people to cast their votes!