diff --git a/spine-cpp/spine-cpp/src/spine/SkeletonJson.cpp b/spine-cpp/spine-cpp/src/spine/SkeletonJson.cpp
index cb41df4c0..ac21f0ab7 100644
--- a/spine-cpp/spine-cpp/src/spine/SkeletonJson.cpp
+++ b/spine-cpp/spine-cpp/src/spine/SkeletonJson.cpp
@@ -1144,7 +1144,7 @@ Animation *SkeletonJson::readAnimation(Json *root, SkeletonData *skeletonData) {
 		TransformConstraintData *constraint = skeletonData->findTransformConstraint(constraintMap->_name);
 		int constraintIndex = skeletonData->_transformConstraints.indexOf(constraint);
 		TransformConstraintTimeline *timeline = new (__FILE__, __LINE__) TransformConstraintTimeline(
-				constraintMap->_size, constraintMap->_size << 2, constraintIndex);
+				constraintMap->_size, constraintMap->_size * 6, constraintIndex);
 
 		float time = Json::getFloat(keyMap, "time", 0);
 		float mixRotate = Json::getFloat(keyMap, "mixRotate", 1);
diff --git a/spine-sfml/cpp/example/testbed.cpp b/spine-sfml/cpp/example/testbed.cpp
index 080e509d2..a883ba146 100644
--- a/spine-sfml/cpp/example/testbed.cpp
+++ b/spine-sfml/cpp/example/testbed.cpp
@@ -33,27 +33,78 @@
 
 using namespace spine;
 
+class NullTextureLoader : public TextureLoader {
+public:
+	virtual void load(AtlasPage &page, const String &path) {}
+
+	virtual void unload(void *texture) {}
+};
+
+class NullAttachmentLoader : public AttachmentLoader {
+	virtual RegionAttachment *newRegionAttachment(Skin &skin, const String &name, const String &path, Sequence *sequence) {
+		return new (__FILE__, __LINE__) RegionAttachment(name);
+	}
+
+	virtual MeshAttachment *newMeshAttachment(Skin &skin, const String &name, const String &path, Sequence *sequence) {
+		return new (__FILE__, __LINE__) MeshAttachment(name);
+	}
+
+	virtual BoundingBoxAttachment *newBoundingBoxAttachment(Skin &skin, const String &name) {
+		return new (__FILE__, __LINE__) BoundingBoxAttachment(name);
+	}
+
+	virtual PathAttachment *newPathAttachment(Skin &skin, const String &name) {
+		return new (__FILE__, __LINE__) PathAttachment(name);
+	}
+
+	virtual PointAttachment *newPointAttachment(Skin &skin, const String &name) {
+		return new (__FILE__, __LINE__) PointAttachment(name);
+	}
+
+	virtual ClippingAttachment *newClippingAttachment(Skin &skin, const String &name) {
+		return new (__FILE__, __LINE__) ClippingAttachment(name);
+	}
+
+	virtual void configureAttachment(Attachment *attachment) {
+	}
+};
+
 int main(void) {
-	String atlasFile("data/spineboy-pma.atlas");
-	String skeletonFile("data/spineboy-pro.skel");
+	String atlasFile("");
+	String skeletonFile("/Users/badlogic/Downloads/catsanddogs2.json");
+	String animation = "";
+
 	float scale = 0.6f;
 	SFMLTextureLoader textureLoader;
-	Atlas *atlas = new Atlas(atlasFile, &textureLoader);
+	NullAttachmentLoader nullLoader;
+	Atlas *atlas = atlasFile.length() == 0 ? nullptr : new Atlas(atlasFile, &textureLoader);
 	SkeletonData *skeletonData = nullptr;
-	if (strncmp(skeletonFile.buffer(), ".skel", skeletonFile.length()) > 0) {
-		SkeletonBinary binary(atlas);
-		binary.setScale(scale);
-		skeletonData = binary.readSkeletonDataFile(skeletonFile);
+	if (strnstr(skeletonFile.buffer(), ".skel", skeletonFile.length()) != nullptr) {
+		SkeletonBinary *binary = nullptr;
+		if (atlas) {
+			binary = new SkeletonBinary(atlas);
+		} else {
+			binary = new SkeletonBinary(&nullLoader);
+		}
+		binary->setScale(scale);
+		skeletonData = binary->readSkeletonDataFile(skeletonFile);
+		delete binary;
 	} else {
-		SkeletonJson json(atlas);
-		json.setScale(scale);
-		skeletonData = json.readSkeletonDataFile(skeletonFile);
+		SkeletonJson *json = nullptr;
+		if (atlas) {
+			json = new SkeletonJson(atlas);
+		} else {
+			json = new SkeletonJson(&nullLoader);
+		}
+		json->setScale(scale);
+		skeletonData = json->readSkeletonDataFile(skeletonFile);
+		delete json;
 	}
 
 	AnimationStateData stateData(skeletonData);
 	SkeletonDrawable drawable(skeletonData, &stateData);
 	drawable.skeleton->setPosition(320, 590);
-	drawable.state->setAnimation(0, "walk", true);
+	if (animation.length() > 0) drawable.state->setAnimation(0, animation, true);
 
 	sf::RenderWindow window(sf::VideoMode(640, 640), "Spine SFML - testbed");
 	window.setFramerateLimit(60);
diff --git a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineAtlasAsset.cpp b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineAtlasAsset.cpp
index d80d1e11a..c1759eed7 100644
--- a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineAtlasAsset.cpp
+++ b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineAtlasAsset.cpp
@@ -58,13 +58,13 @@ void USpineAtlasAsset::Serialize(FArchive &Ar) {
 		importData = NewObject<UAssetImportData>(this, TEXT("AssetImportData"));
 }
 
-void USpineAtlasAsset::PostLoadAssetRegistryTags(const FAssetData& InAssetData,
-	TArray<FAssetRegistryTag>& OutTagsAndValuesToUpdate) const {
+void USpineAtlasAsset::PostLoadAssetRegistryTags(const FAssetData &InAssetData,
+												 TArray<FAssetRegistryTag> &OutTagsAndValuesToUpdate) const {
 	// FIXME: this is a massive hack. It will set the PackageFlags of the FAssetData
 	// in the AssetRegistry to PKG_FilterEditorOnly so the content browser displays it.
 	// This is necessary in UE 5.3 due to a regression in ContentBrowserAssetDataCore::IsPrimaryAsset
 	// See https://github.com/EsotericSoftware/spine-runtimes/issues/2368
-	FAssetData& MutableAssetData = const_cast<FAssetData&>(InAssetData);
+	FAssetData &MutableAssetData = const_cast<FAssetData &>(InAssetData);
 	// MutableAssetData.PackageFlags = EPackageFlags::PKG_FilterEditorOnly;
 	UObject::PostLoadAssetRegistryTags(MutableAssetData, OutTagsAndValuesToUpdate);
 }
diff --git a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineSkeletonDataAsset.cpp b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineSkeletonDataAsset.cpp
index d95094bb9..55e87afab 100644
--- a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineSkeletonDataAsset.cpp
+++ b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Private/SpineSkeletonDataAsset.cpp
@@ -81,13 +81,13 @@ void USpineSkeletonDataAsset::Serialize(FArchive &Ar) {
 }
 
 
-void USpineSkeletonDataAsset::PostLoadAssetRegistryTags(const FAssetData& InAssetData,
-	// FIXME: this is a massive hack. It will set the PackageFlags of the FAssetData
-	// in the AssetRegistry to PKG_FilterEditorOnly so the content browser displays it.
-	// This is necessary in UE 5.3 due to a regression in ContentBrowserAssetDataCore::IsPrimaryAsset
-	// See https://github.com/EsotericSoftware/spine-runtimes/issues/2368
-	TArray<FAssetRegistryTag>& OutTagsAndValuesToUpdate) const {
-	FAssetData& MutableAssetData = const_cast<FAssetData&>(InAssetData);
+void USpineSkeletonDataAsset::PostLoadAssetRegistryTags(const FAssetData &InAssetData,
+														// FIXME: this is a massive hack. It will set the PackageFlags of the FAssetData
+														// in the AssetRegistry to PKG_FilterEditorOnly so the content browser displays it.
+														// This is necessary in UE 5.3 due to a regression in ContentBrowserAssetDataCore::IsPrimaryAsset
+														// See https://github.com/EsotericSoftware/spine-runtimes/issues/2368
+														TArray<FAssetRegistryTag> &OutTagsAndValuesToUpdate) const {
+	FAssetData &MutableAssetData = const_cast<FAssetData &>(InAssetData);
 	// MutableAssetData.PackageFlags = EPackageFlags::PKG_FilterEditorOnly;
 	UObject::PostLoadAssetRegistryTags(MutableAssetData, OutTagsAndValuesToUpdate);
 }
diff --git a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineAtlasAsset.h b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineAtlasAsset.h
index b6a22a808..8b0500ac9 100644
--- a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineAtlasAsset.h
+++ b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineAtlasAsset.h
@@ -71,6 +71,6 @@ protected:
 
 	virtual void PostInitProperties() override;
 	virtual void Serialize(FArchive &Ar) override;
-	virtual void PostLoadAssetRegistryTags(const FAssetData& InAssetData, TArray<FAssetRegistryTag>& OutTagsAndValuesToUpdate) const override;
+	virtual void PostLoadAssetRegistryTags(const FAssetData &InAssetData, TArray<FAssetRegistryTag> &OutTagsAndValuesToUpdate) const override;
 #endif
 };
diff --git a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineSkeletonDataAsset.h b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineSkeletonDataAsset.h
index 407c521e9..af9ade5b0 100644
--- a/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineSkeletonDataAsset.h
+++ b/spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/Public/SpineSkeletonDataAsset.h
@@ -116,7 +116,7 @@ protected:
 	virtual void PostInitProperties() override;
 	virtual void GetAssetRegistryTags(TArray<FAssetRegistryTag> &OutTags) const override;
 	virtual void Serialize(FArchive &Ar) override;
-	virtual void PostLoadAssetRegistryTags(const FAssetData& InAssetData, TArray<FAssetRegistryTag>& OutTagsAndValuesToUpdate) const override;
+	virtual void PostLoadAssetRegistryTags(const FAssetData &InAssetData, TArray<FAssetRegistryTag> &OutTagsAndValuesToUpdate) const override;
 #endif
 
 	void LoadInfo();