http://blogs.technet.com/aqa/archive/2008/12/02/building-a-pivot-view-web-part-based-on-multi-value-column.aspxProblem: Building a dynamic tree of a list based on a choice column (with multi-value select enabled, i.e. checkboxes) can't be done using views and Group By.   Simply because Group By does not list columns with multi-value select in its options.en-USCommunityServer 2.1 SP1 (Build: 61025.2)