I found a real strange bug. A client of mine has two sites. One I host, the other is hosted by a 3th party. Now the client has a domain control panel for the other site and rerouted the other domain to the one I host, but the system just makes a frameset. Not real SEO, but okay. After a few days bug reports came in. Can not log in etc. Can only be the sessions? But after testing I found that the bug only appears in Internet Explorer (tested only 8) and only on the rerouted domain, not the one I host. Fix was easy. Just added a little javascript to break out of the top frameset and everyting was working again. I think it’s Microsoft’s Phishing filter that is kicking in, but have to test further.

Here’s my litte fix: :-)

if(top.frames.length){
top.location.href = self.location.href;
}