onScroll(e) {
      if (this.selectionRequestedByClick) {
        this.selectionRequestedByClick = false;
        return;
      }
      (0, _debounce.default)(this.changeSelectionByScroll.bind(this, e.target.scrollTop), Wizard_1.SCROLL_DEBOUNCE_RATE);
    }
Handles user scrolling with debouncing.
<b>Note:</b> the handler is bound in the template.
@param {MouseEvent} e
@private