Hi xCHM devs,
first of all, I've been using xCHM since a long time (and I hated the way wxHtmlWindow rendered links in wx < 2.7 - i.e. broking the underlining at word boundaries - that's why I provided the patch for fixing the underlining in wx ;)) and I want to say: congrats for the great work!
Second: just two small suggestions for making it look more GTK+-like when compiled against wxGTK 2.8:
1) using wx's stock item IDs (wxID_EXIT, etc) you'll get automatic GTK+ stock icons for the menu items.
2) using wxAboutDialogBox() you can make a prettier about box ;)
very small things but they would improve GTK+ native-ness a lot...