title: SASS user-select mixin without import - compass
body: <p>I'm working on SASS with compass. I've already created some mixins but still, there is one mixin I can't make it to work. That's the user-select one. I know I can import it using @import "compass/css3/user-interface"; but that's not the point. Why my 'handmade' @mixin user-select($value){..} does not seem to work? Is there any known reason?</p>
  
  <pre><code>@mixin user-select($value) {
    -webkit-user-select: $value; 
    -moz-user-select: $value; 
    -ms-user-select: $value; 
    -o-user-select: $value; 
    user-select: $value;    
  }
  
  .myclass {
    @include user-select(none);
  }
  </code></pre>