src/vs/base/browser/ui/splitview/splitview.ts/SplitView/swapViews
class SplitView:	swapViews(from: number, to: number): void {
		if (this.state !== State.Idle) {
			throw new Error('Cant modify splitview');
		}

		if (from > to) {
			return this.swapViews(to, from);
		}

		const fromSize = this.getViewSize(from);
		const toSize = this.getViewSize(to);
		const toView = this.removeView(to);
		const fromView = this.removeView(from);

		this.addView(toView, fromSize, from);
		this.addView(fromView, toSize, to);
	}