/// <summary>
        /// Fired when a key is pressed when the GLControl has focus
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void glControl_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
        {
            if (e.KeyData == Keys.Back)
            {
                editorStateControl.DeleteSelectedPoint();

                bufferControl.Rebuild();
                glControl.Invalidate();
            }
            else if ((e.KeyData & Keys.Control) != 0)
            {
                editorState.ModifierState = EditorStateControl.KeyModifierState.ControlDragging;
            }
            else if ((e.KeyData & Keys.Shift) != 0)
            {
                editorState.ModifierState = EditorStateControl.KeyModifierState.NewPath;
            }
        }