Continuity mistake: When Harry is in Lupin's office, as the Professor says, "I resigned..." his cane leans against the corner of the trunk beside the doorway. Yet when Harry says, "But Dumbledore..." the cane hangs off the center of the trunk. As Harry says, "None of it made any difference," the cane is actually gone, but when Lupin says, "You helped uncover the truth," the cane hangs again. Then when Lupin says, "If I am proud of anything..." the cane leans against the corner, but wait, when Lupin leaves the office the cane hangs off the trunk once again!
Picture added by Super Grover