Here's a simple HTML which does not work. It should display Portal demo in iframe. Works well in Firefox and Chrome. Does not work in IE8.
It was working with previous public release (4.0.7). Does not work with ExtJS 4.1.
HTML Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head></head><body><iframe  frameborder="0" height="2000px" id="itarget" name="itarget" scrolling="auto" src="http://dev.sencha.com/deploy/ext-4.1.0-gpl/examples/portal/portal.html" title="Content" width="100%"></iframe></body></html>
Here's what I get in IE8:
IE8Ext41iframeerror.jpg