The change r24372 | daleanson | 2016-05-05 introduces an oddity in the default fg/bg colors of the StyleEditor using the following values:
fg = jEdit.getActiveView().getForeground();
bg = jEdit.getActiveView().getBackground();
This is quite different from the regular TextArea colors, e.g. on Linux with L&F Gtk+ or Windows with native L&F.
Maybe the following works better:
fg = jEdit.getColorProperty("view.fgColor");
bg = jEdit.getColorProperty("view.bgColor");
On the other hand, only the wrong color value made me aware that the StyleEditor in SyntaxHiliteOptionPane enforced a background color for styles that were previously transparent. So the whole approach may require rethinking.
Yes, those colors make no sense. I've fixed this in revision 24875 to use the default text area bg and fg colors.