<oXygen/> comes along with a powerful outliner which is automatically synchronized with the document changes. The document tree structure is presented as the document is edited. The modified element is immediately revealed and selected in the outliner. Also an element can be selected in the text editor by clicking the corresponding node in the outliner. The outliner uses an extremely fast and robust parser being able to handle XML documents that are not well-formed.

The Outline panel, located in the bottom left part of the main editor window offers the following features:
The XML outliner displays a general tag overview of the current edited XML Document. It shows the hierarchical dependencies between the elements, making it easier for you to see the structure of the document.
The outliner presents a short text that describes each element from the tree. The description is composed of the value of the first attribute and the first words from the text content of the rendered element. The buttons from the outliner toolbar allow you to filter out the attribute and the text values.
When editing, the outliner dynamically follows the introduced modifications scrolling to the node which is currently being modified. This gives you better insight on how the document is affected by the modifications.
The XML outliner can also be used to search for a specific element location and content in the edited document. When you select a node in the outliner tree, the XML document is scrolled to the position of the selected element. Moreover, the content of the tag is selected in the document so you can copy and paste it in other parts of the document.
You can control what elements are displayed in the Outline view by typing element names into a filter box. For example, entering the element name "figure" when editing a DocBook article results in getting immediately a short summary of all the figures from your document.

The next image shows the filtered outliner as a tree. There are presented only the elements that are parents or children of the selected elements. The selected elements are boldfaced.

To make the XML validation errors and warnings easier to spot, the Outline view marks the XML elements having problems with a red or yellow color and with a corresponding icon.

More details about the error are presented in the tool-tip.
