I have just downloaded and installed the latest version 7.2 of Peter Baker's Junicode font. This replaces an earlier version of the font with which I happily created many documents in Scribus.
I opened an old document that used the Junicode font and quickly noted that Scribus added about an m-dash width of space after the lowercase h, but only before certain letters. My Scribus is 1.4.0 on Fedora 16, x86_64. Can someone install this font and see what happens when you type: ha hb hc hd he hf hg hi hj hk hl hm hn ho hp hq hr hs ht hu hv hw hx hy hz I typed the above into LibreOffice Writer and everything appeared normal. When I pasted it into Scribus the extra space appears between h and b, d, f, h, i, j, k and l.
