Working on a web site that dynamically (i.e. upon user action) shows and hides HTML content and Flash content, everything worked as expected in IE9.
When I checked the same page in Chrome 18 and Firefox 12, however, the Flash object would reset everytime I invoked the jQuery .show() method on the object (initialization takes some time for some of the objects I embed).
This behavior has already been mentioned in blogs and support forums.
My solution was to roll-back some of the changes I made, and put the Flash object back to its iframe. Toggling the iframe display does not seem to affect Flash.
Other people worked around this behavior by setting visibility and size, or adding/removing a class that defines display:none.