bug=193835

Missing focus when selected the related checkbox or radiobox in Preference window.
r=kyle.yuan@sun.com sr=jaggernaut@netscape.com

suite/common/pref/pref-advanced.xul

@@ -46,6 +46,9 @@
       var checked = document.getElementById("advancedMailFTP").checked;
       var field = document.getElementById("advancedMailFTPAddress");
       field.disabled = !checked;
+
+      if (! field.disabled)
+        field.focus();
     }
 
     /* 

suite/common/pref/pref-mousewheel.xul

@@ -76,6 +76,9 @@
        el.setAttribute("disabled", "true"); 
      else 
        el.removeAttribute("disabled"); 
+
+     if (!el.disabled)
+       el.focus();
    } 
 
   ]]>

suite/common/pref/pref-offline.xul

@@ -53,6 +53,9 @@
          aField.removeAttribute("disabled"); 
      else 
          aField.setAttribute("disabled", "true"); 
+    
+     if (! aField.disabled)
+       aField.focus();
   } 
 
   </script>