title: MVC 3 Client Side Validation Catches Some ValidationAttributes but not others?
body: <p>I'm confused by this behavior:</p>
  
  <p>I have an out-of-the-box MVC3 app. I haven't really done any customization from the what the scaffolding template gives me.</p>
  
  <p>In web.config, clientsidevalidationenabled and unobtrusivevalidation are both true.</p>
  
  <p>I have a class with one field using the <strong>Required</strong> annotation, one using <strong>StringLength</strong> and one using <strong>RegularExpression</strong>. When I'm editing an object, the textboxes for the properties marked with StringLength &amp; Regex report problems instantly in the UI, but the textbox for the Required doesn't.</p>
  
  <p>If I hit SAVE, then "Model.IsValid" is the controller sess the problem with the missing Required and I get the UI error message next to the text box.</p>
  
  <p>If I view the source of the page, I can see that the markup for the required property does have the dataval-req and other related attributes generated by the Unobtrusive validation.</p>
  
  <p>Is this expected behavior? If it is, what's the reason? If it's not, what might I be doing wrong?</p>
  
  <p>Thanks! :)</p>