title: PerformanceProgressBar eats 50% of CPU even when invisible
body: <p>I am using the PerformanceProgressBar control from the Silverlight Toolkit for Windows Phone.
  I am observing that once a page with a PerformanceProgressBar is shown, the CPU in the emulator goes to 50% and stays there even after the IsIndedeterminate / Visibility / Enabled properties have been disabled.</p>
  
  <p>Has anyone else observed this?</p>
  
  <p>Not sure whether this is an emulator behavior only or it happens on the phone as well.</p>
  
  <p>Thanks in advance.</p>