Condo board managers at 260 Park Avenue South are suing their building’s landlord, Tessler Development, for carving a hole between the structure’s first floor and its basement. The plaintiffs allege that Tessler was not authorized to construct this hole which, reportedly, was meant to serve as the start of a staircase between the two floors in the building, which sits on the corner of 21st Street. Perhaps this indiscretion was merely a straw on the camel’s back, because the plaintiffs’ attorney, Aaron Shmulewitz, said that the conflict between the condo board and the landlord is ongoing. “There are issues with regard to the roof. There are issues with regard to waterproofing. There are issues with regard to the budget,” Shmulewitz said. “There are all sorts of issues.”