Temporary fix for mousewheel problem of select in FF and IE.

Resolve #247.

src/perfect-scrollbar.js

@@ -52,6 +52,8 @@
     };
   };
 
+  var isWebkit = 'WebkitAppearance' in document.documentElement.style;
+
   $.fn.perfectScrollbar = function (suppliedSettings, option) {
 
     return this.each(function () {
@@ -363,6 +365,13 @@
         }
 
         function mousewheelHandler(e) {
+          // FIXME: this is a quick fix for the select problem in FF and IE.
+          // If there comes an effective way to deal with the problem,
+          // this lines should be removed.
+          if (!isWebkit && $this.find('select:focus').length > 0) {
+            return;
+          }
+
           var delta = getDeltaFromEvent(e);
 
           var deltaX = delta[0];