title: I'm not specifying the form action but it (automatically) gives different values in some cases
body: <p>I'm creating my form using the Form helper, so the action of the form is specified automatically....</p>
  
  <p>this form is used for editing a post..<br>
  so, the URL has the structure: <code>mywebsite.com/posts/edit/id</code>
  and the form's action should be automatically generated as <code>posts/edit/id</code></p>
  
  <p>but the problem is, in some cases, I open the HTML code and I find that the form's action is only <code>posts/edit</code> without the <code>id</code> which causes the update to fail...</p>
  
  <p>I spent a lot of time to figure out what situation brings this wrong action:</p>
  
  <ul>
  <li>i'm generating fields dynamically (using javascript &amp; ajax) depending on the post's category..</li>
  <li>when the value of one of the dynamically generated fields is invalid, the generated action becomes <code>posts/edit</code> !!</li>
  </ul>
  
  <p>I really need help, cuz I don't know why this is happening !!!<br>
  and I don't wanna waste more time digging into the core of cakephp...<br>
  so, if any of cakephp experts has an idea about this, plz help me !! </p>
  
  <p>thank you in advance ! </p>