public void Unregister()
{
var t = new MapTree();
var r = new MapNode(t, "r");
ChangeManager manager = new ChangeManager();
manager.RegisterMap(t);
manager.Unregister(t);
r.Text = "changed";
Assert.IsFalse(manager.CanUndo);
}
public void TurnOffChangeManager()
{
ChangeManager.Unregister(this);
ChangeManager = null;
}