title: What does d3.select(this) return?
body: <p>I have an svg group upon which I call a drag function. </p>
  
  <pre><code>var container=d3.select("#id");
  container.call(dragcontainer);
  var dragcontainer = d3.drag()
                          .on("start", function () {})
                          .on("drag", function (d, i) {  
                              //(d3.select(this)).select("rect");
                          })
                          .on("end", function () {});
  </code></pre>
  
  <p>Apparently, <code>d3.select(this)</code> does not return the <code>container</code>, however they are similar (checked through attributes), but just not exactly the same. </p>
  
  <p>Why does this happen? How can I access <code>container</code> within the called function?</p>