The David Zwirner art gallery in Chelsea was just hit with an $8MM lawsuit filed by a collector who claims its owners told a painter he sold one of her works, a move that landed him on her blacklist. Craig Robins says the gallery breached a confidentiality agreement when they told artist Marlene Dumas that they helped him sell her 1994 painting, "Reinhardt's Daughter" (pictured). Robins is now barred from directly buying from her representatives. He seeks $3MM in compensatory damages, plus $5 million for the gallery's "reprehensible motives" and "wanton dishonesty." The gallery told the NY Post that the case has "no merit." Artheads: is it really that bad for a collector to sell a painting?