It appears that the themes have not been coded to support Internet Explorer 7. Some layout components appear misaligned or broken. I understand this is an old browser but it still has a fairly large user base. Are you guys planning IE7 support down the line or are you coding for IE8+ only?
I attached a couple of of IE7 screenshots. The first one is from this forum, the 2nd is from our installation (we are running a custom theme based on CSS-Only Theme. I was able to fix the misaligned Search button that you see in first screenshot in our theme via css override but other elements are more challenging because they use classes with no id hooks.
1. SP Support Forums
2. Our Test Installation (custom theme based on css-only)



