This week Arhaus debuted its 10,000-square-foot furniture showroom at Westfield Montgomery mall. As we reported a few weeks ago, this is a relocation of the retailer’s longtime store on Rockville Pike. Another store we recently previewed, Melashops, has opened its doors near Nordstrom with a colorful collection of South Asian clothing and jewelry. And this week’s other big mall opening is Jolly Yolly Kids, an indoor playground next door to Cheesecake Factory.