         } else {
             to = lineHeight * CGFloat(lineNo) - clipHeight / 2
         }
-        NSAnimationContext.beginGrouping()
-        NSAnimationContext.current().duration = AnimationDuration
         var origin = clipView.bounds.origin
-        origin.y = to
-        clipView.animator().setBoundsOrigin(origin)
-        NSAnimationContext.endGrouping()
+        if origin.y != to {
+            NSAnimationContext.beginGrouping()
+            NSAnimationContext.current().duration = AnimationDuration
+            origin.y = to
+            clipView.animator().setBoundsOrigin(origin)
+            NSAnimationContext.endGrouping()
+        }
     }
 }

    var prevPlayTime: Double = -1
    var prevPlayTimeDate: Date?
    var prevPosition: LyricsPosition?
    
    @IBOutlet weak var window: NSPanel!
    @IBOutlet weak var scrollView: NSScrollView!

                   }
                    prevPosition = pos
                }
            }
        }
    }
