gitk: jumping to next/previos highlighted commit?

Is there a way to jump to the next or previous highlighted commit in
gitk? For searching within a given commit diff, there's the "Search"
button as well as C-s/C-r, but I haven't found any similar controls
for the highlighting.

-- 
Karl Hasselström, kha@treskal.com
      www.treskal.com/kalle