Minor Description
Deleting the only child of a collapsed tree node doesn't update the node's JunctionLink or icon to show that it is now childless.
Error occurs with both org.apache.wicket.markup.html.tree.LinkTree and org.apache.wicket.extensions.markup.html.tree.Tree. However, org.apache.wicket.extensions.markup.html.tree.Tree will update correctly if you select/deselect or try to expand the now childless node.