An Author extension action can have multiple modes, each mode invoking an Author Operation with certain configured parameters. Each action mode has an XPath 2.0 expression for activating it.
For each action mode the application will check if the XPath expression is fulfilled (when it returns a not empty nodes set or a true result). If it is fulfilled, the operation defined in the action mode will be executed.
Two special XPath extension functions are provided: the oxy:allows-child-element() function that you can use to check whether an element is valid in the current context, considering the associated schema and the oxy:current-selected-element() function that you can use to get the currently selected element.