_drawSelectionBox(ctx) {
    if (this.body.selectionBox.show) {
      ctx.beginPath();
      const width =
        this.body.selectionBox.position.end.x -
        this.body.selectionBox.position.start.x;
      const height =
        this.body.selectionBox.position.end.y -
        this.body.selectionBox.position.start.y;
      ctx.rect(
        this.body.selectionBox.position.start.x,
        this.body.selectionBox.position.start.y,
        width,
        height
      );
      ctx.fillStyle = "rgba(151, 194, 252, 0.2)";
      ctx.fillRect(
        this.body.selectionBox.position.start.x,
        this.body.selectionBox.position.start.y,
        width,
        height
      );
      ctx.strokeStyle = "rgba(151, 194, 252, 1)";
      ctx.stroke();
    } else {
      ctx.closePath();
    }
  }
Redraw selection box
@param {CanvasRenderingContext2D} ctx  2D context of a HTML canvas
@private