Attaching a patch to make Sylpheed open URLs with the gnome-open helper tool as opposed to "mozilla -remote 'openURL(%s, new-window)'". Version-Release number of selected component (if applicable): sylpheed-0.9.10-1
Created attachment 98799 [details] patch -p1
looks good. will apply it.
fixed in 0.9.10-2, which will be available soon.