XML Parser Preferences

To configure the XML Parser options, open the Preferences dialog box and go to XML > XML Parser.

The configurable options of the built-in XML parser are as follows:

Enable parser caching (validation and content completion) - Enables re-use of internal models when validating and provides content completion in opened XML files which reference the same schemas (grammars) like DTD, XML Schema, RelaxNG.
Ignore the DTD for validation if a schema is specified - Forces validation against a referenced schema (W3C XML Schema, Relax NG schema) even if the document includes also a DTD DOCTYPE declaration. This option is useful when the DTD declaration is used only to declare DTD entities and the schema reference is used for validation against a W3C XML Schema or a Relax NG schema.
Note: Schematron schemas are treated as additional schemas. The validation of a document associated with a DTD and referencing a Schematron schema is executed against both the DTD and the Schematron schema, regardless of the value of the Ignore the DTD for validation if a schema is specified option.
Enable XInclude processing - Enables XInclude processing. If checked, the XInclude support in Oxygen XML Editor is turned on for validation, rendering in Author mode and transformation of XML documents.
Base URI fix-up - According to the specification for XInclude, processors must add an xml:base attribute to elements included from locations with a different base URI. Without these attributes, the resulting infoset information would be incorrect.
Unfortunately, these attributes make XInclude processing not transparent to Schema validation. One solution to this is to modify your schema to allow xml:base attributes to appear on elements that might be included from different base URIs.

If the addition of xml:base and / or xml:lang is undesired by your application, you can disable base URI fix-up.
Language fix-up - The processor will preserve language information on a top-level included element by adding an xml:lang attribute if its include parent has a different [language] property. If the addition of xml:lang is undesired by your application, you can disable the language fix-up.
DTD post-validation - Enable this option to validate an XML file against the associated DTD, after all the content merged to the current XML file using XInclude was resolved. If you disable this option, the current XML file is validated against the associated DTD before all the content merged to the current XML file using XInclude is resolved.