src/vs/base/browser/ui/sash/sash.ts/Sash/orthogonalEndSash
class Sash:	set orthogonalEndSash(sash: Sash | undefined) {
		this.orthogonalEndDragHandleDisposables.clear();
		this.orthogonalEndSashDisposables.clear();

		if (sash) {
			const onChange = (state: SashState) => {
				this.orthogonalEndDragHandleDisposables.clear();

				if (state !== SashState.Disabled) {
					this._orthogonalEndDragHandle = append(this.el, $('.orthogonal-drag-handle.end'));
					this.orthogonalEndDragHandleDisposables.add(toDisposable(() => this._orthogonalEndDragHandle!.remove()));
					this.orthogonalEndDragHandleDisposables.add(new DomEmitter(this._orthogonalEndDragHandle, 'mouseenter')).event
						(() => Sash.onMouseEnter(sash), undefined, this.orthogonalEndDragHandleDisposables);
					this.orthogonalEndDragHandleDisposables.add(new DomEmitter(this._orthogonalEndDragHandle, 'mouseleave')).event
						(() => Sash.onMouseLeave(sash), undefined, this.orthogonalEndDragHandleDisposables);
				}
			};

			this.orthogonalEndSashDisposables.add(sash.onDidEnablementChange(onChange, this));
			onChange(sash.state);
		}

		this._orthogonalEndSash = sash;
	}