not only in my theme, but also in the demo theme http://www.kriesi.at/themes/corona/portfolio-item/asdf/
I've discovered obviously a bug:
In theme options I have set at "Enter a page slug that should be used for your portfolio single items" my own: "portfoliomalerei" (in demo theme it is obviously set as "portfolio-item").
So far, so good, see it in action here in demo theme:
Now take a look at the URL of this page in the browser:
and you see, that for these category slugs a complete other portfolio"slug" is used, in demo theme "portfolio_entries".
And now this archive page has - the wrong! - URL of http://www.kriesi.at/themes/corona/portfolio_entries/css/, although in theme settings, the portfolio slug is set as "portfolio-items".
In my own CORONA version it is exactly the same behaviour.
So what can I do, that also these archive pages uses exactly that portfolio slug, too, that I have set in the theme options for portfolio pages?
Because at the moment, I have set it in theme options -> Portfolio to "portfoliomalerei" and the archive pages for a portfolio category is ".../portfolio_entries/schwebende-bilder/"