The Shops of Grand Avenue will soon have one more vacancy to fill. The downtown Milwaukee mall's recently renovated, West Wisconsin Avenue-facing OfficeMax is closing Feb. 21, an employee confirmed Tuesday. Boca Raton, Fla.-based Office Depot Inc. (NYSE: ODP) acquired OfficeMax in late 2013, and later announced plans to shutter 400 stores. OfficeMax occupies 8,000 square feet, downsized from an original 15,000-square-foot footprint when the company retooled its space at the Grand Avenue in 2013. Dan…