The View Actions tab opens when you open the To Do List or when you select 
on the To Do List tool bar.
When the View Actions tab first opens it is not active, it only becomes active when you select a Document Type tab that is set to Flat view. View Actions is not available from the Document List tab or the Inactive Tasks tab.
In the View Actions > Tree View you can select attributes of any of the item types listed in the current To Do List view, and add them to the To Do List as non-actionable, view only values. This allows you to view attributes, and their values, from the item types database even if it is not in the To Do List. For example, you can display in the To Do List a comparison between a task property value and the value stored in the database. By adding the attribute from the Task Properties and adding the same attribute from the View Actions tab you can then compare the value from the database and the new value.
Any attribute added from the View Actions tab has the prefix in the column header Current, for example; Current Length.
From the View Actions tool bar you can select 
to regenerate the To Do List. Regeneration returns the To Do List to its original
state.