Major Description
From the roadmap document for Wicket 7:
In a few places in core we have hardcoded css strings like wicket_orderUp and classes used inside the feedback panel - these should be made into application settings so they can be configured to conform to the application's css infrastructure.
Once we extract wicket_orderUp we should get rid of cssprovider and defaultcssprovider classes.
getApplication().getCssSettings().setSortOrderDownClass("sort-order-down");