title: predict(....,type="prob"), without type="prob" is fine, type="prob" with two classes is fine. but type="prob" with multiple classes is wrong
body: <p>My code for the <code>predict</code> function is as following:</p>
  
  <pre><code>predict(Flaw.rf, newdata = newtest[-grep("Product", colnames(newtest))], 
          type="prob")
  </code></pre>
  
  <p>When I get rid of the <code>type="prob"</code> there is no problem. And if I change the product to just <code>2</code>, there is also no problem. However, when the product is multi-classes and I apply <code>type="prob"</code>, there is something wrong. It says <code>undefined columns selected</code></p>