In the latest public release of IE10 under windows 7. I have found an issue where Flash content in an iframe whic is removed from DOM does not get removed from display.
This was discovered in context of a real site but can be trivially recreated in a simple demo. Please view this example: http://jsfiddle.net/VcxXF/3/
Note that this occurs on both IE10 and IE9 browser/document modes. It *may* occur in earlier version modes however jsFiddle fails to load the example in these modes anyway.
IE version: 10.0.9200.16540
Flash version (just updated): 11,7,700,169