title: Expand specific rows in Angular-ui-grid
body: <p>I'm using angular-ui-grid 3.0.5 with the treeview extension to display a tree. The data loads normally, everything works as expected, except that <code>expandRow</code> fails silently.</p>
  
  <p>My use case is this: suppose we have a path like a > b > c and I need c shown to the user as preselected. I know the selection is correctly done because when I manually expand the parent rows, the child row is indeed selected. </p>
  
  <p>Should I call <code>expandAllRows</code>, all rows would be expanded. However, calling <code>expandRow</code> with references on rows a and b taken from <code>gridOptions.data</code> leads to nothing happening: all rows will remain collapsed.</p>
  
  <p>Is there any precaution to be taken that I have maybe overlooked, or is this a bug?</p>
  
  <p>There's <a href="https://github.com/angular-ui/ui-grid/issues/3841#issuecomment-152575219" rel="nofollow">one mention</a> in a closed issue that may be related to this but problem I'm having, but I'm not even sure it's related, given how dry the comment/solution was.</p>
  
  <p>There's no example of using <code>expandRow</code> in the documentation but it's in both the API and the source code.</p>