title: ListCollectionView's live shaping bug
body: <p>After digging deeper, why live shaping, in detail the automatic sorting of groups by name, is not working, I decided to wrote a small test application, solution download is here:</p>
  
  <p><a href="https://www.dropbox.com/s/lwhjfti46a06dmq/LiveShapingTest.zip?dl=0" rel="nofollow noreferrer">here</a></p>
  
  <p>Following, a description of the problem: I use an ObservableCollection of Person objects, with Age and Name properties (with NPC). I create a ListCollectionView bound to a  DataGrid with a custom GroupStyle to expose an Expander</p>
  
  <p>For this view I set:</p>
  
  <ul>
  <li>GroupDescription to Age</li>
  <li>SortDescription to Age (to sort the groups)</li>
  <li>SortDescription to Name</li>
  </ul>
  
  <p>After start a DispatcherTimer recalculates all Ages of each Person to a random value between 30 and 45.</p>
  
  <p>At runtime the fault: for about 60-70% of all dynamic resorts of the groups, the sorting order is right e.g. for example 31 before 34 before 41 before 45. But sometimes a 30th number is between two 40th numbers, and that's wrong. Where is the problem and how can I solve? By the way, the problem only occures for group ordering.</p>
  
  <p>BTW: For what purpose is the LiveSortingProperties collection, setting a  SortDescription and IsLiveSorting=True obviously activates live shaping, In which situation I should add a string to this collection?</p>
  
  <p>Here is a screenshot of the wrong group sorting:</p>
  
  <p><a href="https://i.stack.imgur.com/2D4TY.png" rel="nofollow noreferrer">Example Picture of wrong sorting</a>:</p>
  
  <p><a href="https://i.stack.imgur.com/8NV2P.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8NV2P.png" alt="enter image description here"></a></p>