/// <summary>
        /// Before the editor events
        /// </summary>
        public override void BeforeEditorEvents()
        {
            CheckActivation();

            if (!IsActivated)
            {
                return;
            }

            if (Event.current.type != EventType.KeyDown)
            {
                return;
            }

            if (Event.current.keyCode == KeyCode.A &&
                Event.current.modifiers == EventModifiers.Shift)
            {
                if (NodeEditor.AreAllNodesSelected())
                {
                    NodeEditor.UnselectAllNodes();
                }
                else
                {
                    NodeEditor.SelectAllNodes();
                }
            }
        }