diff --git a/spine-csharp/src/Animation.cs b/spine-csharp/src/Animation.cs
index cb824f0df..2fdbebc5d 100644
--- a/spine-csharp/src/Animation.cs
+++ b/spine-csharp/src/Animation.cs
@@ -637,10 +637,6 @@ namespace Spine {
 			frames = new float[frameCount * 3];
 		}
 
-		public float[] getFrames () {
-			return frames;
-		}
-
 		/** Sets the time, mix and bend direction of the specified keyframe. */
 		public void setFrame (int frameIndex, float time, float mix, int bendDirection) {
 			frameIndex *= 3;
diff --git a/spine-csharp/src/Bone.cs b/spine-csharp/src/Bone.cs
index fdad97882..058493342 100644
--- a/spine-csharp/src/Bone.cs
+++ b/spine-csharp/src/Bone.cs
@@ -134,8 +134,8 @@ namespace Spine {
 			float m00 = this.m00, m10 = this.m10, m01 = this.m01, m11 = this.m11;
 			Skeleton skeleton = this.skeleton;
 			if (skeleton.flipX != (skeleton.flipY != yDown)) {
-				m00 *= -1;
-				m11 *= -1;
+				m00 = -m00;
+				m11 = -m11;
 			}
 			float invDet = 1 / (m00 * m11 - m01 * m10);
 			localX = (dx * m00 * invDet - dy * m01 * invDet);
diff --git a/spine-csharp/src/IkConstraint.cs b/spine-csharp/src/IkConstraint.cs
index 5a6160842..6261e083a 100644
--- a/spine-csharp/src/IkConstraint.cs
+++ b/spine-csharp/src/IkConstraint.cs
@@ -38,8 +38,8 @@ namespace Spine {
 		internal IkConstraintData data;
 		internal List<Bone> bones = new List<Bone>();
 		internal Bone target;
-		internal int bendDirection = 1;
-		internal float mix = 1;
+		internal int bendDirection;
+		internal float mix;
 
 		public IkConstraintData Data { get { return data; } }
 		public List<Bone> Bones { get { return bones; } }
@@ -48,6 +48,8 @@ namespace Spine {
 		public float Mix { get { return mix; } set { mix = value; } }
 
 		public IkConstraint (IkConstraintData data, Skeleton skeleton) {
+			if (data == null) throw new ArgumentNullException("data cannot be null.");
+			if (skeleton == null) throw new ArgumentNullException("skeleton cannot be null.");
 			this.data = data;
 			mix = data.mix;
 			bendDirection = data.bendDirection;
diff --git a/spine-csharp/src/Skeleton.cs b/spine-csharp/src/Skeleton.cs
index 02aa9653f..359b41afd 100644
--- a/spine-csharp/src/Skeleton.cs
+++ b/spine-csharp/src/Skeleton.cs
@@ -37,7 +37,7 @@ namespace Spine {
 		internal List<Bone> bones;
 		internal List<Slot> slots;
 		internal List<Slot> drawOrder;
-		internal List<IkConstraint> ikConstraints = new List<IkConstraint>();
+		internal List<IkConstraint> ikConstraints;
 		private List<List<Bone>> boneCache = new List<List<Bone>>();
 		internal Skin skin;
 		internal float r = 1, g = 1, b = 1, a = 1;
@@ -74,12 +74,9 @@ namespace Spine {
 			bones = new List<Bone>(data.bones.Count);
 			foreach (BoneData boneData in data.bones) {
 				Bone parent = boneData.parent == null ? null : bones[data.bones.IndexOf(boneData.parent)];
-				bones.Add(new Bone(boneData, this, parent));
-			}
-
-			foreach(Bone b in bones){
-				if(b.Parent != null)
-					b.Parent.children.Add(b);
+				Bone bone = new Bone(boneData, this, parent);
+				if (parent != null) parent.children.Add(bone);
+				bones.Add(bone);
 			}
 
 			slots = new List<Slot>(data.slots.Count);
diff --git a/spine-csharp/src/SkeletonData.cs b/spine-csharp/src/SkeletonData.cs
index edc5d648b..48b500363 100644
--- a/spine-csharp/src/SkeletonData.cs
+++ b/spine-csharp/src/SkeletonData.cs
@@ -136,7 +136,7 @@ namespace Spine {
 			return null;
 		}
 
-		// --- IK
+		// --- IK constraints.
 
 		/// <returns>May be null.</returns>
 		public IkConstraintData FindIkConstraint (String ikConstraintName) {
diff --git a/spine-csharp/src/SkeletonJson.cs b/spine-csharp/src/SkeletonJson.cs
index 8ad08bb6e..57784e5d5 100644
--- a/spine-csharp/src/SkeletonJson.cs
+++ b/spine-csharp/src/SkeletonJson.cs
@@ -96,7 +96,7 @@ namespace Spine {
 				skeletonData.hash = (String)skeletonMap["hash"];
 				skeletonData.version = (String)skeletonMap["spine"];
 				skeletonData.width = GetFloat(skeletonMap, "width", 0);
-				skeletonData.height = GetFloat(skeletonMap, "width", 1);
+				skeletonData.height = GetFloat(skeletonMap, "height", 0);
 			}
 			
 			// Bones.
diff --git a/spine-libgdx/src/com/esotericsoftware/spine/Bone.java b/spine-libgdx/src/com/esotericsoftware/spine/Bone.java
index 6022a6fc3..d2e81bea8 100644
--- a/spine-libgdx/src/com/esotericsoftware/spine/Bone.java
+++ b/spine-libgdx/src/com/esotericsoftware/spine/Bone.java
@@ -264,8 +264,8 @@ public class Bone {
 		float m00 = this.m00, m10 = this.m10, m01 = this.m01, m11 = this.m11;
 		Skeleton skeleton = this.skeleton;
 		if (skeleton.flipX != skeleton.flipY) {
-			m00 *= -1;
-			m11 *= -1;
+			m00 = -m00;
+			m11 = -m11;
 		}
 		float invDet = 1 / (m00 * m11 - m01 * m10);
 		world.x = (x * m00 * invDet - y * m01 * invDet);