If you are in the text-control, just use return to get the next occurrence.
You can not use F3 here, because it's bound to the "normal" search, which belongs to the C::B-core.
I will commit a change, that uses Shift+Return to jump to the previous occurence, soon.
If you select the regex-search (not yet in the manual) you can only jump to the next occurrence due to wxWidgets limitations.