diff --git a/src/components/FixedJointComponents.cpp b/src/components/FixedJointComponents.cpp
index d7c8c129..4ae8552a 100644
--- a/src/components/FixedJointComponents.cpp
+++ b/src/components/FixedJointComponents.cpp
@@ -163,7 +163,7 @@ void FixedJointComponents::moveComponentToIndex(uint32 srcIndex, uint32 destInde
     new (mR2World + destIndex) Vector3(mR2World[srcIndex]);
     new (mI1 + destIndex) Matrix3x3(mI1[srcIndex]);
     new (mI2 + destIndex) Matrix3x3(mI2[srcIndex]);
-    new (mImpulseTranslation + destIndex) Vector3(mImpulseRotation[srcIndex]);
+    new (mImpulseTranslation + destIndex) Vector3(mImpulseTranslation[srcIndex]);
     new (mImpulseRotation + destIndex) Vector3(mImpulseRotation[srcIndex]);
     new (mInverseMassMatrixTranslation + destIndex) Matrix3x3(mInverseMassMatrixTranslation[srcIndex]);
     new (mInverseMassMatrixRotation + destIndex) Matrix3x3(mInverseMassMatrixRotation[srcIndex]);
diff --git a/src/systems/SolveFixedJointSystem.cpp b/src/systems/SolveFixedJointSystem.cpp
index 6f31972a..e120bfcc 100644
--- a/src/systems/SolveFixedJointSystem.cpp
+++ b/src/systems/SolveFixedJointSystem.cpp
@@ -355,7 +355,7 @@ void SolveFixedJointSystem::solvePositionConstraint() {
 
         // Compute the pseudo velocity of body 1
         const Vector3 v1 = inverseMassBody1 * linearImpulseBody1;
-        Vector3 w1 = mFixedJointComponents.mI2[i] * angularImpulseBody1;
+        Vector3 w1 = mFixedJointComponents.mI1[i] * angularImpulseBody1;
 
         // Update the body position/orientation of body 1
         x1 += v1;
diff --git a/testbed/CMakeLists.txt b/testbed/CMakeLists.txt
index ea09cef7..7305e9cf 100755
--- a/testbed/CMakeLists.txt
+++ b/testbed/CMakeLists.txt
@@ -8,6 +8,7 @@ project(Testbed)
 set(NANOGUI_BUILD_EXAMPLES OFF CACHE BOOL " " FORCE)
 set(NANOGUI_BUILD_PYTHON  OFF CACHE BOOL " " FORCE)
 set(NANOGUI_INSTALL       OFF CACHE BOOL " " FORCE)
+set(NANOGUI_BACKEND       OpenGL CACHE BOOL " " FORCE)
 
 # ---- Make sure to recursively clone all the git submodules for external libraries (nanogui) --- #
 find_package(Git QUIET)
diff --git a/testbed/src/TestbedApplication.cpp b/testbed/src/TestbedApplication.cpp
index 337ea96a..9a467044 100755
--- a/testbed/src/TestbedApplication.cpp
+++ b/testbed/src/TestbedApplication.cpp
@@ -103,12 +103,15 @@ void TestbedApplication::init() {
     glGetIntegerv(GL_MAJOR_VERSION, &glMajorVersion);
     glGetIntegerv(GL_MINOR_VERSION, &glMinorVersion);
 
+#ifdef GL_DEBUG_OUTPUT
+
     if (glMajorVersion > 4 || (glMajorVersion == 4 && glMinorVersion >= 3)) {
 
         // Enable OpenGL error reporting
         glEnable(GL_DEBUG_OUTPUT);
         glDebugMessageCallback(onOpenGLError, 0);
     }
+#endif
 
     mIsInitialized = true;
 }
@@ -332,6 +335,7 @@ void TestbedApplication::notifyEngineSetttingsChanged() {
 void GLAPIENTRY TestbedApplication::onOpenGLError(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length,
                               const GLchar* message, const void* userParam ) {
 
+#ifdef GL_DEBUG_OUTPUT
     if (type == GL_DEBUG_TYPE_ERROR) {
         /*
         fprintf( stderr, "GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n",
@@ -339,6 +343,8 @@ void GLAPIENTRY TestbedApplication::onOpenGLError(GLenum source, GLenum type, GL
                     type, severity, message );
          */
     }
+#endif
+
 }
 
 // Compute the FPS