RE: Copy/iSearch/Occur on folded outline view?

[Drew Adams]

> > You may also consider to define an toggle command for
> > `search-invisible', and bind it in `isearch-mode-map'
> 
> very nice, thank you, I had to install cl-lib first, but then it works
> like a charm, very helpfull when even the collapsed headlines 
> (3 levels) of your .emacs are some 260 lines. 

FYI, Isearch+ also provides toggle key `C-+' for this.

However, unlike Michael's suggestion, it does not cycle among `t', `nil', and
`open'.  Instead, it toggles between `nil' and whichever of `t' and `open' you
prefer (see option `search-invisible').
http://www.emacswiki.org/cgi-bin/wiki/IsearchPlus