After you upgrade to Microsoft Dynamics CRM 2011 and then open forms of certain entities, you receive an error message that resembles the following:
There was an error with this field's customized event.
Field:window
Event:onload
Error: 'crmForm.all.tab2Tab.style' is null or not an object.
Field:window
Event:onload
Error: 'crmForm.all.tab2Tab.style' is null or not an object.