message: bind instead of second member var
diff: @@ -40,7 +40,7 @@ export class Resizer {
  vertical: "resizer-vertical",
  resizing: "resizer-resizing",
  };
  - this.mouseDownHandler = (event) => this._onMouseDown(event);
  + this._onMouseDown = this._onMouseDown.bind(this);
  }
  setClassNames(classNames) {
  @@ -48,11 +48,11 @@ export class Resizer {
  }
  attach() {
  - this.container.addEventListener("mousedown", this.mouseDownHandler, false);
  + this.container.addEventListener("mousedown", this._onMouseDown, false);
  }
  detach() {
  - this.container.removeEventListener("mousedown", this.mouseDownHandler, false);
  + this.container.removeEventListener("mousedown", this._onMouseDown, false);
  }
  /**
  