diff --git a/build/MidiControl/Classes/IControlMIDI.cs b/build/MidiControl/Classes/IControlMIDI.cs
index c0dfe17..5bf02d4 100644
--- a/build/MidiControl/Classes/IControlMIDI.cs
+++ b/build/MidiControl/Classes/IControlMIDI.cs
@@ -120,13 +120,10 @@ Deinitializes the output device
         */
         public void DisconnectDevice()
         {
-            lock (lockDevice)
+            if (device != null)
             {
-                if (device != null)
-                {
-                    device.Dispose();
-                    device = null;
-                }
+                device.Dispose();
+                device = null;
             }
         }
 
diff --git a/build/MidiControl/Classes/RotaryKnob.xaml.cs b/build/MidiControl/Classes/RotaryKnob.xaml.cs
index 6bb39a7..6d4902f 100644
--- a/build/MidiControl/Classes/RotaryKnob.xaml.cs
+++ b/build/MidiControl/Classes/RotaryKnob.xaml.cs
@@ -150,7 +150,7 @@ private void SetRotation(ref double dAngle)
                 dAngle = dAngle < Constants.KNOB_ROTATION_MIN ? Constants.KNOB_ROTATION_MIN : dAngle;
 
                 //Calculate the knob status and set its angle
-                Status = Steps[(int)Math.Floor((dAngle - Constants.KNOB_ROTATION_MIN) / (Constants.KNOB_ROTATION_MAX - Constants.KNOB_ROTATION_MIN) * (Steps.Count - 1))];
+                Status = Steps[(int)Math.Round((dAngle - Constants.KNOB_ROTATION_MIN) / (Constants.KNOB_ROTATION_MAX - Constants.KNOB_ROTATION_MIN) * (Steps.Count - 1))];
                 transformKnob.Angle = Constants.KNOB_ROTATION_MIN + (Constants.KNOB_ROTATION_MAX - Constants.KNOB_ROTATION_MIN) * (double)Steps.IndexOf(Status) / (Steps.Count - 1);
             }
             else