The left-hand pane or 'tree pane' allows you to organize your data, while the right-hand pane or 'article pane' allows you to type in new articles - it contains the editor.
The tree consists of 'nodes' or branches. By default, any node has a yellow folder icon and a node title. Each 'Node' in the tree pane corresponds to an 'Article' (the text inside the article pane). When you click on a node in the left-hand pane (tree pane), its corresponding article will be loaded inside the right-hand pane (article pane).
The topmost node is the 'root node'. Inside a TreePad file there can be only one root node from which all other nodes spring.
The tree represents the organization of your data, it enables you to easily browse and re-organize the information by navigating and re-arranging the tree. Any node can contain other nodes - these are its 'child nodes'. 'Child nodes' can contain 'child nodes' of their own - and so on. This recursive capability gives TreePad its power.
A collection of child nodes and their parent node is called a subtree. A subtree can be expanded/collapsed using the little [+] or [-] sign to the left of the node title of the subtree. A collapsed subtree does not show its children, an expanded subtree shows all its children. A ** fully ** expanded subtree shows not only its children but also ** all ** its descendants, In other words, it also shows the children of the children, the children of the children of the children, and so on.
An 'expanded subtree' (= the children are visible) always has a [-] sign which you can click with your left mouse button to collapse it. A 'collapsed subtree' (= the children are hidden) always has a [+] sign that can be used to expand it.