title: WinRt App keyUp and keyDown events does not working after navigated from my page
body: <p>My code for handling the KeyDown and the KeyUp events on the page:</p>
  
  <pre><code>    protected override void OnNavigatedTo(NavigationEventArgs e)
          {
              base.OnNavigatedTo(e);
                  Window.Current.CoreWindow.KeyDown += GameArea_KeyDown;
                  Window.Current.CoreWindow.KeyUp += GameArea_KeyUp;
  
          }
          protected override void OnNavigatedFrom(NavigationEventArgs e)
          {
              base.OnNavigatedFrom(e);
  
                  Window.Current.CoreWindow.KeyDown -= GameArea_KeyDown;
                  Window.Current.CoreWindow.KeyUp -= GameArea_KeyUp;
  
  
          }
          ....
  </code></pre>
  
  <p>I have  2 pages in my application. This is  Page1 and Page2. On the Page1 I have one  button for navigation to the Page2. On Page2 I have 2 elements. They are: button2 for proceeding to the Page 1 and GameArea element.  I'm using MVVM and comands to navigation on the pages.</p>
  
  <p>My work steps: On the Page1 I clicked the button1 and navigated to the Page2. On the Page2 I worked with KeyUp and KeyDown events in the  GameArea element. After some work, I clicked button2 and went back to the Page1. On the Page1 I again clicked button1 and went to the Page2, but KeyUp and KeyDown events did not work. I waited a few seconds (30-50) and typed some keys on the keyboard. After that , key up/down events worked well. </p>
  
  <p>What is happening with keyUp and keyDown events? </p>
  
  <p>I'm apologize for my bad English.</p>