title: .FindControl always returns null
body: <p>I have two methods. The first creates one table dynamically, and I add that table into a PlaceHolder.</p>
  
  <pre><code>private void generateData(){
      Table tbl = new Table();
      tbl.ID = "table1";
      holder_info.Controls.Add(tbl);
      // ...adding tr's and td's....
      // ...adding CheckBox in tds....
  }
  </code></pre>
  
  <p>If I do .FindControl("...") inside this method I can find the control using:</p>
  
  <pre><code>CheckBox check = (CheckBox)holder_info.FindControl("checkbox1");
  </code></pre>
  
  <p>It's OK, but not what I pretend.</p>
  
  <p>In the second method, I want to check whether the user checked checkBox and did something, but I can't find the control (it always returns null).</p>
  
  <pre><code>protected void saveInfo_Click(object sender, ImageClickEventArgs e)
  {
    CheckBox check = (CheckBox)holder_info.FindControl("checkbox1");
    if(check.checked){ ... }
  }
  </code></pre>
  
  <p>Also, if I try to find the control "table1", I get null.</p>
  
  <p>Why does this happen?</p>