Selecting a Root Map
Oxygen XML Author plugin allows you to select a DITA map as a key space, or
            root map, for all the other DITA maps and topics in the project. Specifying the
            correct root map helps to prevent validation problems when you work with
            keyrefs and also acts as the foundation for content completion. All the
            keys that are defined in a root map are available in the maps that
            the root map contains.
         
There are several ways to select or change the root map:
- The easiest method is to use the Root map drop-down menu in the DITA Maps Manager toolbar to select the appropriate root map.
 - If you insert a key reference using the Cross Reference
                  action from the 
Link drop-down
                  menu (from the toolbar or Link submenu of the contextual menu) and
                  keys are not gathered from the expected DITA map, you can change the root map by using
                  the Change Root Map link in the Choose Key
                  dialog box that is opened when you click the 
Choose Key Reference button.
                - If you insert a content key reference or key reference using the
                  
Reuse Content action (from
                  the toolbar, DITA menu, or Reuse submenu of
                  the contextual menu) and keys are not gathered from the expected DITA map, you can
                  change
                  the root map by using  the Change Root Map link in the
                  Choose Key dialog box that is opened when you click the
                  
Choose Key Reference
                  button.
                
To watch our video demonstration about the DITA Root Map support, go to https://www.oxygenxml.com/demo/DITA_Root_Map.html.