src/vs/base/browser/ui/grid/gridview.ts/BranchNode/removeChild
class BranchNode:	removeChild(index: number, sizing?: Sizing): void {
		if (index < 0 || index >= this.children.length) {
			throw new Error('Invalid index');
		}

		this.splitview.removeView(index, sizing);
		this._removeChild(index);
		this.onDidChildrenChange();
	}