The Context Window is available in XSLT debugging sessions only; it is not available in XQuery debugging sessions.
During the processing of the XSLT stylesheet, the processor's context is always within a template that matches some sequence (of nodes or atomic values). The Context Window displays the current processing context, which could be a sequence of nodes, a single node, or an atomic value (such as a string). Depending on the kind of a context item, its value or attribute/s is/are displayed. For example, if the context item is an element, the element's attributes are displayed. If the context item is an attribute or text node, the node's value is displayed.
Clicking an entry in the Context Window, displays that item in the XML document. If the XML document is not currently displayed in the interface, a window for the XML document will be opened.