Replace AddConnections by a HitObjects property.

osu.Game.Modes.Osu/Objects/Drawables/Connections/ConnectionRenderer.cs

@@ -7,13 +7,15 @@ using System.Collections.Generic;
 
 namespace osu.Game.Modes.Osu.Objects.Drawables.Connections
 {
+    /// <summary>
+    /// Connects hit objects visually, for example with follow points.
+    /// </summary>
     public abstract class ConnectionRenderer<T> : Container
         where T : HitObject
     {
         /// <summary>
-        /// Create drawables inside this container, connecting hit objects visually, for example with follow points.
+        /// Hit objects to create connections for
         /// </summary>
-        /// <param name="hitObjects">Hit objects to create connections for</param>
+        public abstract IEnumerable<T> HitObjects { get; set; }
-        public abstract void AddConnections(IEnumerable<T> hitObjects);
     }
 }

osu.Game.Modes.Osu/Objects/Drawables/Connections/FollowPointRenderer.cs

@@ -10,18 +10,53 @@ namespace osu.Game.Modes.Osu.Objects.Drawables
 {
     public class FollowPointRenderer : ConnectionRenderer<OsuHitObject>
     {
+        private int pointDistance = 32;
         /// <summary>
         /// Determines how much space there is between points.
         /// </summary>
-        public int PointDistance = 32;
+        public int PointDistance
+        {
+            get { return pointDistance; }
+            set
+            {
+                if (pointDistance == value) return;
+                pointDistance = value;
+                update();
+            }
+        }
 
+        private int preEmpt = 800;
         /// <summary>
         /// Follow points to the next hitobject start appearing for this many milliseconds before an hitobject's end time.
         /// </summary>
-        public int PreEmpt = 800;
+        public int PreEmpt
-
-        public override void AddConnections(IEnumerable<OsuHitObject> hitObjects)
         {
+            get { return preEmpt; }
+            set
+            {
+                if (preEmpt == value) return;
+                preEmpt = value;
+                update();
+            }
+        }
+
+        private IEnumerable<OsuHitObject> hitObjects;
+        public override IEnumerable<OsuHitObject> HitObjects
+        {
+            get { return hitObjects; }
+            set
+            {
+                hitObjects = value;
+                update();
+            }
+        }
+
+        private void update()
+        {
+            Clear();
+            if (hitObjects == null)
+                return;
+
             OsuHitObject prevHitObject = null;
             foreach (var currHitObject in hitObjects)
             {

osu.Game.Modes.Osu/UI/OsuPlayfield.cs

@@ -73,9 +73,9 @@ namespace osu.Game.Modes.Osu.UI
 
         public override void PostProcess()
         {
-            connectionLayer.AddConnections(HitObjects.Children
+            connectionLayer.HitObjects = HitObjects.Children
                 .Select(d => (OsuHitObject)d.HitObject)
-                .OrderBy(h => h.StartTime));
+                .OrderBy(h => h.StartTime);
         }
 
         private void judgement(DrawableHitObject h, JudgementInfo j)