Add the root-catalog.xml catalog to the oXygen XML Editor
For IXIASOFT CCMS to locate the DTDs for the DITA objects and elements in your documentation, you must add the root-catalog.xml file to the oXygen editor.
The root-catalog.xml dynamically points to the master-catalog.xml catalog file, which contains the list of all the catalogs used by the CCMS. If you add a new catalog to the system, make sure to add it to the master-catalog.xml catalog file as described in the Integrating DTDs for DITA 1.3 into the Content Store document.
The catalogs are now available to the oXygen editor.