src/vs/base/browser/ui/splitview/splitview.ts/SplitView/setViewVisible
class SplitView:	setViewVisible(index: number, visible: boolean): void {
		if (index < 0 || index >= this.viewItems.length) {
			throw new Error('Index out of bounds');
		}

		const viewItem = this.viewItems[index];
		viewItem.setVisible(visible);

		this.distributeEmptySpace(index);
		this.layoutViews();
		this.saveProportions();
	}