src/vs/workbench/contrib/preferences/browser/settingsWidgets.ts/ListSettingListModel/selectPrevious
class ListSettingListModel:	selectPrevious(): void {
		if (typeof this._selectedIdx === 'number') {
			this._selectedIdx = Math.max(this._selectedIdx - 1, 0);
		} else {
			this._selectedIdx = 0;
		}
	}