src/vs/base/browser/ui/sash/sash.ts/Sash/getOrthogonalSash
class Sash:	private getOrthogonalSash(e: PointerEvent): Sash | undefined {
		if (!e.target || !(e.target instanceof HTMLElement)) {
			return undefined;
		}

		if (e.target.classList.contains('orthogonal-drag-handle')) {
			return e.target.classList.contains('start') ? this.orthogonalStartSash : this.orthogonalEndSash;
		}

		return undefined;
	}