diff --git a/src/Collections/EcsSpan.cs b/src/Collections/EcsSpan.cs
index 1880656..8f0a26d 100644
--- a/src/Collections/EcsSpan.cs
+++ b/src/Collections/EcsSpan.cs
@@ -36,7 +36,7 @@ namespace DCFApixels.DragonECS
         public bool IsNull
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _values.IsEmpty;
+            get => _worldID == 0;
         }
         #endregion
 
diff --git a/src/EcsWorld.cs b/src/EcsWorld.cs
index 195a115..dc825ca 100644
--- a/src/EcsWorld.cs
+++ b/src/EcsWorld.cs
@@ -18,6 +18,8 @@ namespace DCFApixels.DragonECS
             public short componentsCount;
             [FieldOffset(4)]
             public bool isUsed;
+            //[FieldOffset(5)]
+            //public bool isLocked;
             public EntitySlot(short gen, short componentsCount, bool isUsed)
             {
                 this.gen = gen;
diff --git a/src/EcsWorld.pools.cs b/src/EcsWorld.pools.cs
index be7f207..f8b2eeb 100644
--- a/src/EcsWorld.pools.cs
+++ b/src/EcsWorld.pools.cs
@@ -209,6 +209,7 @@ namespace DCFApixels.DragonECS
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void RegisterEntityComponent(int entityID, int componentTypeID, EcsMaskChunck maskBit)
         {
+            UpVersion();
             _poolComponentCounts[componentTypeID]++;
             _entities[entityID].componentsCount++;
             _entityComponentMasks[entityID * _entityComponentMaskLength + maskBit.chankIndex] |= maskBit.mask;
@@ -216,6 +217,7 @@ namespace DCFApixels.DragonECS
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void UnregisterEntityComponent(int entityID, int componentTypeID, EcsMaskChunck maskBit)
         {
+            UpVersion();
             _poolComponentCounts[componentTypeID]--;
             var count = --_entities[entityID].componentsCount;
             _entityComponentMasks[entityID * _entityComponentMaskLength + maskBit.chankIndex] &= ~maskBit.mask;
diff --git a/src/entlong.cs b/src/entlong.cs
index f9690fc..6f22edd 100644
--- a/src/entlong.cs
+++ b/src/entlong.cs
@@ -223,7 +223,7 @@ namespace DCFApixels.DragonECS
     }
 
 
-    [DebuggerTypeProxy(typeof(entlong.DebuggerProxy))]
+    [DebuggerTypeProxy(typeof(DebuggerProxy))]
     public readonly struct EntitySlotInfo : IEquatable<EntitySlotInfo>
     {
         public readonly int id;
@@ -280,5 +280,31 @@ namespace DCFApixels.DragonECS
             world = this.world;
         }
         #endregion
+
+
+        internal class DebuggerProxy
+        {
+            private List<object> _componentsList = new List<object>();
+            private entlong _value;
+            public long full { get { return _value.full; } }
+            public int id { get { return _value.id; } }
+            public int gen { get { return _value.gen; } }
+            public int world { get { return _value.world; } }
+            public EntState State { get { return _value.IsNull ? EntState.Null : _value.IsAlive ? EntState.Alive : EntState.Dead; } }
+            public EcsWorld EcsWorld { get { return EcsWorld.GetWorld(world); } }
+            public IEnumerable<object> components
+            {
+                get
+                {
+                    _value.World.GetComponents(_value.ID, _componentsList);
+                    return _componentsList;
+                }
+            }
+            public DebuggerProxy(EntitySlotInfo value)
+            {
+                _value = new entlong(value.id, value.gen, value.world);
+            }
+            public enum EntState { Null, Dead, Alive, }
+        }
     }
 }