XQuery Validation
With Oxygen XML Editor, you can validate your documents before using them in your transformation scenarios. The validation uses the Saxon 12.3 PE, EE, or HE processor, or you can use some database engines (such as MarkLogic or eXist) if you installed them. Any other XQuery processor that offers an XQJ API implementation can also be used. This is in conformance with the XQuery Working Draft. The processor is used in two cases: validation of the expression and execution. Although the execution implies a validation, it is faster to check the expression syntactically, without executing it. The errors that occurred in the document are presented in the messages view at the bottom of editor window, with a full description message. As with all error messages, if you click an entry, the line where the error appeared is highlighted.
The 
Validation options button, available in the menu, allows quick access to the XQuery
options in the Oxygen XML Editor preferences.
When you open an XQuery document from a connection that supports validation (for example, MarkLogic, or eXist), by default Oxygen XML Editor uses this connection for validation. If you open an XQuery file using a MarkLogic connection, the validation resolves imports better.