The recent release of IE 9 saw some changes in the way Javascript is handled. Because of this, you may have noticed some functions of Open Leads quit working in the manner you would expect (such as the popup calendar when you schedule a task). We will be updating our code in the next couple of weeks, but in the mean time, if you configure your IE to work in “Compatibility Mode,” everything will work properly again.
To switch IE 9 to Compatibility Mode follow the instructions here: http://support.microsoft.com/kb/956197#2 – or when you navigate to Open Leads, you may see an icon in your URL bar that looks like a torn sheet of paper. Click on this to toggle Compatibility mode on.