Extensions are also called plugins, they can be hooked onto widgets in various combinations and provide wanted options. Currently there is a couple of extensions TreeDisableWrapExtension Tree extension, disables wrapping for tree nodes. Also it fixes IE bug when an 'unwrappable' node (e.g single word) will move to next line if no space left. TreeDocIconExtension Tree extension, places icon to the left of a node, depening on nodeType property TreeEmphaseOnSelect Selector extension, highlights currently selected nodes TreeDeselectOnDblselect Selector extension, deselects a selected node when it is clicked. Usually, one should ctrl-click, or click another node. TreeLinkExtension Tree extension, turns labels into links, merges object property into <a> tag