Scenario: 1) 'treeView' is created with 'treeData' and added to the component hierarchy. 2) 'treeView' adds itself as a ListListener on 'treeData', causing 'treeData' to maintain a reference to 'treeView' 3) 'treeView' is removed from the component hierarchy, but the user still needs a reference to 'treeData'.
Result: 'treeView' never falls out of scope, and the user has no way to release the reference to it since it used a private handler as its event listener. Should such components only listen for data events while they're attached to the component hierarchy? -T
