On my website, IE7 seems to be ignoring certain CSS attribute selectors. The strange thing is that it only happens when the page comes from the production server. If I have the
I just ran into this with both IE8 and IE9 and I found the solution!
Now this may not translate exactly to IE7, but it should point you in the right direction.
It appears that Microsoft considers a host part of the "intranet" when it is:
It also looks like nothing is considered "intranet" if the client system is not joined to a domain.