I wanted to do the same thing. I found that using a category name using some Unicode non-printing characters worked. I inserted them into a document using MS Word...Insert symbol.... and then selected them and did a cut and then pasted them into the Zapitti category field. Try Unicode points like alternative space characters such as http://www.fileformat.info/info/unic...2000/index.htm
. Zappitti kept the string after restart. After I deleted the Dune export directory and did a complete export to Dune, I also saw that no text was displayed below the category/genre icons. It's a pity that the Zappiti developers don't just allow an empty string so you don't have to explore hacks like this.