src/vs/base/browser/ui/list/listView.ts/ListView/updateScrollWidth
class ListView:	private updateScrollWidth(): void {
		if (!this.horizontalScrolling) {
			return;
		}

		let scrollWidth = 0;

		for (const item of this.items) {
			if (typeof item.width !== 'undefined') {
				scrollWidth = Math.max(scrollWidth, item.width);
			}
		}

		this.scrollWidth = scrollWidth;
		this.scrollableElement.setScrollDimensions({ scrollWidth: scrollWidth === 0 ? 0 : (scrollWidth + 10) });
	}