Some pages have portlets that control the content of other portlets on the same page. These portlets are called controlling and subordinate portlets, respectively. Clicking on the item's name (indicated in blue) in a controlling portlet updates the content of the subordinate portlets with details about the selected item.
Not all portlets on a page are subordinate. For example in a MIMIX instance, the Nodes portlet on the Data Groups page is not subordinate to the Data Groups portlet, but the Data Group Details and Activities portlet is subordinate.