/**
* Removes all listeners attached to the document and that manage focus.
*/
public void dispose() {
EventTarget target = (EventTarget)document;
target.removeEventListener("click", mouseclickListener, true);
target.removeEventListener("mouseover", mouseoverListener, true);
target.removeEventListener("mouseout", mouseoutListener, true);
target.removeEventListener("DOMFocusIn", domFocusInListener, true);
target.removeEventListener("DOMFocusOut", domFocusOutListener, true);
lastFocusEventTarget = null;