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

		const cachedVisibleSize = this.getViewCachedVisibleSize(from);
		const sizing = typeof cachedVisibleSize === 'undefined' ? this.getViewSize(from) : Sizing.Invisible(cachedVisibleSize);
		const view = this.removeView(from);
		this.addView(view, sizing, to);
	}