This is the continuation of those tasks :

http://www.google-melange.com/gci/task/view/google/gci2013/5783157492154368

https://www.google-melange.com/gci/task/view/google/gci2014/5317479186300928

What you have to do :

• Make the knob to don't overflow after reaching the max value. This is a potentially dangerous behaviour, as it may happen to do it for mistake, as the primary use of this knob is audio you may burn a pair of speakers potentially. 
• Make the knob to move using the mouse scroll.
• Investigate and solve the crash at close of the testing app.