title: Disappearing knockout.js bindings on history.back() when using pjax
body: <p>I have a test case here: <a href="http://tremby.net/knockouttest/page1.php" rel="nofollow">http://tremby.net/knockouttest/page1.php</a></p>
  
  <p>I'm using pjax for page transitions. Clicking between page 1 and page 2 on the test case above loads the two pages asynchronously and then replaces the contents of the <code>#main</code> element. A browser history state is pushed in the process, so the URL in the location bar is updated and the back button is supposed to get us back where we were.</p>
  
  <p>The list on page 1 is populated with knockout's <code>foreach</code> binding and the <code>List</code> model I've defined (in the inline script in the head). On <code>ready</code> on page 1, an inline script runs <code>ko.applyBindings</code> and so the list is populated.</p>
  
  <p>The "add item" button adds an item to the view model, which knockout then adds to the list.</p>
  
  <p>Adding a few items and then going to page 2, then back to page 1, the list is fresh with its initial 3 items, and the add item button still works. This is fine for our use case.</p>
  
  <p>Adding a few items and then going to page 2, but then using the browser's back button to go back to page 1, on the other hand, is where my issue is. The new items are still visible (which is good, and 
  vital for our use case when the browser's back button is used), but the "add item" button is now broken. The code to push the new item to the <code>observableArray</code> is definitely running, but it seems the bindings have disappeared and so knockout doesn't know to add a new DOM element.</p>
  
  <p>I can't run the <code>ko.applyBindings</code> function again on <code>popstate</code>, or knockout will now think I want each of the now-existing items to be duplicated for each item in the list, and after that each click to "add item" gives multiple new items.</p>
  
  <p>I have a strong feeling there's something obvious I'm missing, but I can't find anything which looks like it'll help in the documentation. Any help would be much appreciated.</p>