title: jQuery 1.6: backgroundPosition vs backgroundPositionX and FF4 compatibility
body: <p>In an attempt to upgrade the jQuery plugin 'iCheckbox' (http://stackoverflow.com/questions/6032538/) to work above jQuery 1.4.4 I found out that the use of</p>
  
  <pre><code> animate({backgroundPosition:'10px 0px'})
  </code></pre>
  
  <p>needed to be changed to </p>
  
  <pre><code>animate({backgroundPositionX: '10px', backgroundPositionY:  '0px'})
  </code></pre>
  
  <p>as only properties with one parameter should be used. So far, this makes sense, but wait.. while it's working fine in Safari and Chrome, it's not working in FF4 (all on Mac)..</p>
  
  <p>So i tried this and that and finally found out that if I change it to</p>
  
  <pre><code>animate({backgroundPosition: '10px'})
  </code></pre>
  
  <p>It works everywhere!
  But what's going on here? Now that I just give one parameter, it works, but I'm not specifying if it's for X or Y axis (so it defaults to X axis it seems.. but what if I want it to work on Y axis?)</p>
  
  <p>This seems wierd, and my solutions here can't be the correct way of doing it.. so I need some advice:</p>
  
  <p>What's going on?</p>
  
  <p>How should background position be animated using jQuery 1.4 - 1.6 so that it works across browsers?</p>