Textboxes disabled via xbl properties don't have proper styling (86899). r=kerz sr=ben

suite/common/pref/pref-advanced.xul

@@ -47,6 +47,8 @@
       var checked = document.getElementById("advancedMailFTP").checked;
       var field = document.getElementById("advancedMailFTPAddress");
       field.disabled = !checked;
+      if (checked)
+        field.focus();
     }
 
 	/*