diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
new file mode 100644
index 00000000..2fe98d26
--- /dev/null
+++ b/.github/FUNDING.yml
@@ -0,0 +1 @@
+patreon: craftworkgames
diff --git a/Source/Demos/Features/Demos/CollisionDemo.cs b/Source/Demos/Features/Demos/CollisionDemo.cs
index 77977625..dcc448b9 100644
--- a/Source/Demos/Features/Demos/CollisionDemo.cs
+++ b/Source/Demos/Features/Demos/CollisionDemo.cs
@@ -36,21 +36,21 @@ namespace Features.Demos
             _blankTexture = new Texture2D(GraphicsDevice, 1, 1);
             _blankTexture.SetData(new[] { Color.WhiteSmoke });
 
-            var demoBall1 = new DemoBall(new Sprite(_spikeyBallTexture))
+            var spikyBallLeft = new DemoBall(new Sprite(_spikeyBallTexture))
             {
                 Position = new Vector2(200, 240),
                 Velocity = new Vector2(0, -120)
             };
-            _actors.Add(demoBall1);
+            _actors.Add(spikyBallLeft);
 
-            var demoBall2 = new DemoBall(new Sprite(_spikeyBallTexture))
+            var spikeyBallRight = new DemoBall(new Sprite(_spikeyBallTexture))
             {
                 Position = new Vector2(600, 240),
                 Velocity = new Vector2(0, 120)
             };
-            _actors.Add(demoBall2);
+            _actors.Add(spikeyBallRight);
 
-            var controllableBall = new DemoBall(new Sprite(_spikeyBallTexture))
+            var controllableBall = new ControllableBall(new Sprite(_spikeyBallTexture))
             {
                 Position = new Vector2(400, 240),
                 Velocity = new Vector2(0, 0)
@@ -58,26 +58,26 @@ namespace Features.Demos
             _actors.Add(controllableBall);
             _controllableBall = controllableBall;
 
-            var wall1 = new DemoWall(new Sprite(_blankTexture))
+            var topWall = new DemoWall(new Sprite(_blankTexture))
             {
                 Bounds = new RectangleF(0, 0, 800, 20),
                 Position = new Vector2(0, 0)
             };
-            _actors.Add(wall1);
+            _actors.Add(topWall);
 
-            var wall2 = new DemoWall(new Sprite(_blankTexture))
+            var bottomWall = new DemoWall(new Sprite(_blankTexture))
             {
                 Position = new Vector2(0, 460),
                 Bounds = new RectangleF(0, 0, 800, 20)
             };
-            _actors.Add(wall2);
+            _actors.Add(bottomWall);
 
-            var centerWall = new DemoWall(new Sprite(_blankTexture))
+            var spikeyBallCenter = new StationaryBall(new Sprite(_spikeyBallTexture))
             {
-                Bounds = new RectangleF(0, 0, 50, 50),
-                Position = new Vector2(400, 200)
+                Position = new Vector2(400, 240),
+                Velocity = Vector2.Zero,
             };
-            _actors.Add(centerWall);
+            _actors.Add(spikeyBallCenter);
 
             foreach (var actor in _actors)
             {
@@ -126,13 +126,6 @@ namespace Features.Demos
             foreach (var actor in _actors)
             {
                 actor.Draw(_spriteBatch);
-                if (actor.Bounds is RectangleF rect)
-                {
-                    _spriteBatch.Draw(_blankTexture, rect.ToRectangle(), Color.WhiteSmoke);
-                } else if (actor.Bounds is CircleF circle)
-                {
-                    _spriteBatch.Draw(_blankTexture, circle.Position, Color.WhiteSmoke);
-                }
             }
             _spriteBatch.End();
 
@@ -153,9 +146,10 @@ namespace Features.Demos
             Bounds = sprite.GetBoundingRectangle(new Transform2());
         }
 
-
-        public Vector2 Offset { get; set; }
-
+        /// <summary>
+        /// Gets or sets the actor's position and updates teh actor's bounds
+        /// position.
+        /// </summary>
         public Vector2 Position
         {
             get { return _position; }
@@ -166,8 +160,20 @@ namespace Features.Demos
             }
         }
 
+        /// <summary>
+        /// Gets or sets the actor's collision bounds.
+        /// </summary>
         public IShapeF Bounds { get; set; }
 
+        /// <summary>
+        /// Gets or sets how far the actor's collision bounds are offset from 
+        /// the actor's position.
+        /// </summary>
+        public Vector2 Offset { get; set; }
+
+        /// <summary>
+        /// Gets or sets the actor's velocity.
+        /// </summary>
         public Vector2 Velocity { get; set; }
 
         public virtual void OnCollision(CollisionEventArgs collisionInfo)
@@ -201,14 +207,12 @@ namespace Features.Demos
     {
         public DemoBall(Sprite sprite) : base(sprite)
         {
-            Offset = new Vector2(75, 75);
             Bounds = new CircleF(Position + Offset, 60);
         }
 
         public override void Update(GameTime gameTime)
         {
             base.Update(gameTime);
-            Bounds.Position = Position;
         }
 
         public override void OnCollision(CollisionEventArgs collisionInfo)
@@ -220,5 +224,40 @@ namespace Features.Demos
         }
     }
 
+    /// <summary>
+    /// Ball that doesn't move when collided with.
+    /// </summary>
+    class StationaryBall : DemoBall
+    {
+        public StationaryBall(Sprite sprite) : base(sprite)
+        {
+        }
+
+        public override void OnCollision(CollisionEventArgs collisionInfo)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Player controlled ball.
+    /// </summary>
+    class ControllableBall : DemoBall
+    {
+        public ControllableBall(Sprite sprite) : base(sprite)
+        {
+            Bounds = new CircleF(Position + Offset, 60);
+        }
+
+        public override void Update(GameTime gameTime)
+        {
+            base.Update(gameTime);
+        }
+
+        public override void OnCollision(CollisionEventArgs collisionInfo)
+        {
+            Position -= collisionInfo.PenetrationVector;
+        }
+    }
+
     #endregion
 }
\ No newline at end of file
diff --git a/Source/MonoGame.Extended.Collisions/QuadTree/CollisionComponent.cs b/Source/MonoGame.Extended.Collisions/QuadTree/CollisionComponent.cs
index c8e009d3..7d4b9b2f 100644
--- a/Source/MonoGame.Extended.Collisions/QuadTree/CollisionComponent.cs
+++ b/Source/MonoGame.Extended.Collisions/QuadTree/CollisionComponent.cs
@@ -36,20 +36,13 @@ namespace MonoGame.Extended.Collisions
         /// <param name="gameTime"></param>
         public override void Update(GameTime gameTime)
         {
-            // Update bounding box locations.
-            foreach (var value in _targetDataDictionary.Values)
-            {
-                _collisionTree.Remove(value);
-                value.Bounds = value.Target.Bounds;
-                _collisionTree.Insert(value);
-            }
-
             // Detect collisions
             foreach (var value in _targetDataDictionary.Values)
             {
+                _collisionTree.Remove(value);
+
                 var target = value.Target;
-                var collisions =_collisionTree.Query(target.Bounds)
-                    .Where(data => data.Target != target);
+                var collisions =_collisionTree.Query(target.Bounds);
 
                 // Generate list of collision Infos
                 foreach (var other in collisions)
@@ -61,7 +54,9 @@ namespace MonoGame.Extended.Collisions
                     };
 
                     target.OnCollision(collisionInfo);
+                    value.Bounds = value.Target.Bounds;
                 }
+                _collisionTree.Insert(value);
             }
         }
 
@@ -156,7 +151,10 @@ namespace MonoGame.Extended.Collisions
 
         private static Vector2 PenetrationVector(CircleF circ1, CircleF circ2)
         {
-            Debug.Assert(circ1.Intersects(circ2));
+            if (!circ1.Intersects(circ2))
+            {
+                return Vector2.Zero;
+            }
 
             var displacement = Point2.Displacement(circ1.Center, circ2.Center);
 
diff --git a/Source/MonoGame.Extended.Entities/World.cs b/Source/MonoGame.Extended.Entities/World.cs
index a4f34d47..022d4b8c 100644
--- a/Source/MonoGame.Extended.Entities/World.cs
+++ b/Source/MonoGame.Extended.Entities/World.cs
@@ -26,6 +26,9 @@ namespace MonoGame.Extended.Entities
             foreach (var drawSystem in _drawSystems)
                 drawSystem.Dispose();
 
+            _updateSystems.Clear();
+            _drawSystems.Clear();
+            
             base.Dispose();
         }
 
diff --git a/Source/MonoGame.Extended.Tiled/TiledMap.cs b/Source/MonoGame.Extended.Tiled/TiledMap.cs
index e2328b7c..d9b1d14b 100644
--- a/Source/MonoGame.Extended.Tiled/TiledMap.cs
+++ b/Source/MonoGame.Extended.Tiled/TiledMap.cs
@@ -69,6 +69,10 @@ namespace MonoGame.Extended.Tiled
 		private void AddLayer(TiledMapLayer layer, bool root)
         {
 			if (root) _layers.Add(layer);
+			
+			if (_layersByName.ContainsKey(layer.Name))
+				throw new ArgumentException($"The TiledMap '{Name}' contains two or more layers named '{layer.Name}'. Please ensure all layers have unique names.");
+
 			_layersByName.Add(layer.Name, layer);
 
 			switch(layer)
diff --git a/Source/MonoGame.Extended/Collections/Bag.cs b/Source/MonoGame.Extended/Collections/Bag.cs
index cfa59689..292c1d19 100644
--- a/Source/MonoGame.Extended/Collections/Bag.cs
+++ b/Source/MonoGame.Extended/Collections/Bag.cs
@@ -85,11 +85,11 @@ namespace MonoGame.Extended.Collections
             if(Count == 0)
                 return;
 
-            Count = 0;
-
             // non-primitive types are cleared so the garbage collector can release them
             if (!_isPrimitive)
                 Array.Clear(_items, 0, Count);
+
+            Count = 0;
         }
 
         public bool Contains(T element)
@@ -191,4 +191,4 @@ namespace MonoGame.Extended.Collections
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Source/MonoGame.Extended/Math/ShapeExtensions.cs b/Source/MonoGame.Extended/Math/ShapeExtensions.cs
index 51ea932e..30a0b59b 100644
--- a/Source/MonoGame.Extended/Math/ShapeExtensions.cs
+++ b/Source/MonoGame.Extended/Math/ShapeExtensions.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Net.NetworkInformation;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 using MonoGame.Extended.Shapes;
@@ -276,6 +277,21 @@ namespace MonoGame.Extended
             DrawPolygon(spriteBatch, new Vector2(x, y), CreateCircle(radius, sides), color, thickness);
         }
 
+        /// <summary>
+        ///     Draw an ellipse.
+        /// </summary>
+        /// <param name="spriteBatch">The destination drawing surface</param>
+        /// <param name="center">Center of the ellipse</param>
+        /// <param name="radius">Radius of the ellipse</param>
+        /// <param name="sides">The number of sides to generate.</param>
+        /// <param name="color">The color of the ellipse.</param>
+        /// <param name="thickness">The thickness of the line around the ellipse.</param>
+        public static void DrawEllipse(this SpriteBatch spriteBatch, Vector2 center, Vector2 radius, int sides,
+            Color color, float thickness = 1f)
+        {
+            DrawPolygon(spriteBatch, center, CreateEllipse(radius.X, radius.Y, sides), color, thickness);
+        }
+
         private static Vector2[] CreateCircle(double radius, int sides)
         {
             const double max = 2.0*Math.PI;
@@ -291,5 +307,20 @@ namespace MonoGame.Extended
 
             return points;
         }
+
+        private static Vector2[] CreateEllipse(float rx, float ry, int sides)
+        {
+            var vertices = new Vector2[sides];
+
+            var t = 0.0;
+            var dt = 2.0 * Math.PI / sides;
+            for (var i = 0; i < sides; i++, t += dt)
+            {
+                var x = (float)(rx * Math.Cos(t));
+                var y = (float)(ry * Math.Sin(t));
+                vertices[i] = new Vector2(x, y);
+            }
+            return vertices;
+        }
     }
 }
\ No newline at end of file