1. A method of tracking movement of one or more objects on a touch surface of a touch-sensitive apparatus, the touch-sensitive apparatus being operable to propagate light by internal reflections inside a light transmissive panel from a plurality of incoupling points to a plurality of outcoupling points so as to illuminate the touch surface from within the light transmissive panel, wherein at least one light detector is optically coupled to the outcoupling points to generate an output signal representing received light at the outcoupling points, wherein the method operates in a time sequence of repetitions, each repetition comprising: processing the output signal to generate an interaction pattern that indicates local changes in interaction on the touch surface; processing the interaction pattern for identification of apparent peaks; and updating, based on the apparent peaks, existing movement trajectories of objects deemed to exist on the touch surface in a preceding repetition; wherein said method further comprises an error suppression process which is executed at least intermittently in said time sequence of repetitions and which comprises: processing the apparent peaks and/or the existing movement trajectories to identify implicated trajectories with a potential tracking problem; defining at least two movement propositions for each implicated trajectory; and causing an evaluation of said at least two movement propositions in one or more subsequent repetitions.