title: Event when exiting GridView's reorder mode on Windows Phone 8.1
body: <p>I am creating a WinRT-flavored Windows Phone 8.1 app. It uses a <code>GridView</code> to show many tiles that users can tap to execute commands. Users can also hold a tile to enter <code>ReorderMode</code> for the <code>GridView</code>. I enable reordering when the user holds a tile by <a href="https://stackoverflow.com/questions/23875849/winrt-8-1-phone-listview-reordering">setting ReorderMode</a>. Since each tile contains a button with a command bound to it, I also set <code>IsEnabled = false</code> for the button in each tile. This allows the user to reorder tiles without triggering commands.</p>
  
  <p>My problem is re-enabling the button in each tile when the user exits <code>ReorderMode</code>. By default, a user can tap the back button to exit <code>ReorderMode</code>, but I have not found any event to listen to. Is there an event that fires when <code>ReorderMode</code> is disabled that I can listen for to re-enable the button in each tile? Subscribing to <code>HardwareButtons.BackPressed</code> does not work.</p>