static void removeFocusListenerFromTree(Component comp) {
// The exact opposite of addFocusListenerToTree.
comp.removeFocusListener(_AWTFocusListener);
if (comp instanceof Container) {
Container cont = (Container)comp;
cont.removeContainerListener(_AWTContainerListener);
int n = cont.getComponentCount();
for (int i = 0; i < n; i++)
removeFocusListenerFromTree(cont.getComponent(i));
}
}