New York gallerist Jack Tilton testified at federal court in Manhattan that South African-born artist Marlene Dumas has kept a list of those to whom she no longer wants to sell her paintings because she believes they turn over her paintings too quickly. Tilton testified after being subpoenaed in a case filed by Miami collector Craig Robins. Tilton told the court other established collectors and dealers, such as Richard Cooper and Daniel Holtz, were also on Dumas’ list.