Automatic validation as well as validate on request operations are available while editing documents in the Author editor. A detailed description of the document validation process and its configuration is described in section Validating Documents.
Error presenting in Oxygen XML Editor plugin Author editor
A fragment with a validation error or warning will be marked by underlining the error region with a red color. The same will happen for a validation warning, only the color will be yellow instead of red.
Status messages from every validation action are logged into the Console view.