Another patch This one simply adds a utility method SwingUtils.createEmptyBorder(int, int, int, int), and changes all calls to BorderFactory.createEmptyBorder() to call the SwingUtils method instead. This allows us to return an EmptyBorderUIResource instead of a regular EmptyBorder.
Again, this has no visual effect on WebLookAndFeel itself, but allows its custom borders to be cleaned up when the user switches the LookAndFeel at runtime. There's still a long way to go, but this is a good first step.
Patch file is attached this time.