src/vs/base/browser/ui/actionbar/actionbar.ts/ActionBar/getWidth
class ActionBar:	getWidth(index: number): number {
		if (index >= 0 && index < this.actionsList.children.length) {
			const item = this.actionsList.children.item(index);
			if (item) {
				return item.clientWidth;
			}
		}

		return 0;
	}