when I have Datebox or Combobox inside a Groupbox from version 6.5.2 we get a bad flickering ;-(
This happened only if the Groupbox has caption with an image.
See the difference in my test1.jsp page with or without remark of code self.setImage("images.png"), also if image is found or not.
This happened also on .zul page (I sent an example of .jsp page)
In the version 6.5.1 this flickering is not present.