Suffering its third significant setback in court just this month, the manufacturer of Splenda, the nation’s best-selling sugar substitute, has lost its bid for an injunction against the manufacturer of a generic version of its product over its use of “virtually identical” packaging.

In the suit, Splenda’s maker, McNeil Nutritionals, claimed that Heartland Sweeteners violated trade dress law by selling its store-brand generic sucralose in packages that mimic Splenda’s color scheme, graphics and package sizes.